2000 (number)

2000 (two thousand) is the natural number following 1999 and preceding 2001.

See also: millennium, year 2000 AD, Y2K. Two thousand is the highest number expressible using only two unmodified characters in roman numerals (MM). Two thousand is also:

• In the name of the products Lever 2000 and Grecian 2000, Windows 2000
• In Star Trek, the registry number of the USS Excelsior, NX-2000 in Star Trek III: The Search for Spock, and NCC-2000 commanded by Hikaru Sulu in Star Trek VI: The Undiscovered Country.
• The postal code for Antwerp (Belgium)

Selected numbers in the range 2001-2999

• 2001 - sphenic number
• 2003 - Sophie Germain prime
• 2008 - Current year (Gregorian Calendar)
• 2016 - triangular number
• 2017 - Mertens function zero
• 2020 - sum of the totient function for the first 81 integers
• 2024 - tetrahedral number
• 2025 - <math>45^2</math>, sum of the cubes of the first nine integers, centered octagonal number
• 2027 - safe prime
• 2029 - member of the Mian-Chowla sequence
• 2030 - <math>21^2 + 22^2 + 23^2 + 24^2</math>, <math>25^2 + 26^2 + 27^2</math>
• 2031 - centered pentagonal number
• 2039 - Sophie Germain prime, safe prime
• 2047 - super-Poulet number, Woodall number, decagonal number
• 2048 - power of two
• 2056 - magic constant of n×n normal magic square and n-Queens Problem for n = 16.
• 2060 - sum of the totient function for the first 82 integers
• 2063 - Sophie Germain prime, safe prime
• 2069 - Sophie Germain prime
• 2070 - pronic number
• 2080 - triangular number
• 2093 - Mertens function zero
• 2095 - Mertens function zero
• 2096 - Mertens function zero
• 2097 - Mertens function zero
• 2099 - Mertens function zero, safe prime, highly cototient number
• 2100 - Mertens function zero
• 2101 - centered heptagonal number
• 2107 - member of a Ruth-Aaron pair with 2108 (first definition)
• 2108 - member of a Ruth-Aaron pair with 2107 (first definition)
• 2109 - square pyramidal number
• 2112 - The break-through album of the band Rush
• 2113 - Mertens function zero, Proth prime
• 2116 - <math>46^2</math>
• 2117 - Mertens function zero
• 2119 - Mertens function zero
• 2120 - Mertens function zero
• 2122 - Mertens function zero
• 2125 - nonagonal number
• 2127 - sum of the first 34 primes
• 2129 - Sophie Germain prime
• 2135 - Mertens function zero
• 2136 - Mertens function zero
• 2138 - Mertens function zero
• 2141 - Sophie Germain prime
• 2142 - sum of the totient function for the first 83 integers
• 2145 - triangular number
• 2162 - pronic number
• 2166 - sum of the totient function for the first 84 integers
• 2169 - Leyland number
• 2171 - Mertens function zero
• 2172 - Mertens function zero
• 2175 - smallest number requiring 143 seventh powers for Waring representation
• 2176 - pentagonal pyramidal number, centered pentagonal number
• 2179 - Wedderburn-Etherington number
• 2187 - <math>3^7</math>, vampire number, perfect totient number
• 2188 - Motzkin number
• 2197 - <math>13^3</math>
• 2199 - perfect totient number
• 2205 - odd abundant number
• 2207 - safe prime, Lucas prime
• 2208 - Keith number
• 2209 - <math>47^2</math>, centered octagonal number
• 2211 - triangular number
• 2223 - Kaprekar number
• 2230 - sum of the totient function for the first 85 integers
• 2232 - decagonal number
• 2254 - member of the Mian-Chowla sequence
• 2255 - octahedral number
• 2256 - pronic number
• 2269 - cuban prime
• 2272 - sum of the totient function for the first 86 integers
• 2273 - Sophie Germain prime
• 2276 - sum of the first 35 primes, centered heptagonal number
• 2278 - triangular number
• 2287 - balanced prime
• 2294 - Mertens function zero
• 2295 - Mertens function zero
• 2296 - Mertens function zero
• 2299 - member of a Ruth-Aaron pair with 2300 (first definition)
• 2300 - tetrahedral number, member of a Ruth-Aaron pair with 2299 (first definition)
• 2301 - nonagonal number
• 2304 - <math>48^2</math>
• 2306 - Mertens function zero
• 2309 - primorial prime, Mertens function zero, highly cototient number
• 2310 - 5th primorial
• 2311 - primorial prime
• 2321 - Mertens function zero
• 2322 - Mertens function zero
• 2326 - centered pentagonal number
• 2328 - sum of the totient function for the first 87 integers
• 2331 - centered cube number
• 2338 - Mertens function zero
• 2339 - Sophie Germain prime
• 2346 - triangular number
• 2351 - Sophie Germain prime
• 2352 - pronic number
• 2357 - Smarandache-Wellin prime
• 2368 - sum of the totient function for the first 88 integers
• 2378 - Pell number
• 2379 - member of the Mian-Chowla sequence
• 2393 - Sophie Germain prime
• 2397 - sum of the squares of the first ten primes
• 2399 - Sophie Germain prime
• 2400 - perfect score on SAT tests administered after 2005
• 2401 - <math>7^4</math>, <math>49^2</math>, centered octagonal number
• 2415 - triangular number
• 2417 - balanced prime
• 2425 - decagonal number
• 2427 - sum of the first 36 primes
• 2437 - cuban prime
• 2447 - safe prime
• 2450 - pronic number
• 2456 - sum of the totient function for the first 89 integers
• 2458 - centered heptagonal number
• 2459 - Sophie Germain prime, safe prime
• 2465 - magic constant of n×n normal magic square and n-Queens Problem for n = 17, Carmichael number
• 2470 - square pyramidal number
• 2480 - sum of the totient function for the first 90 integers
• 2481 - centered pentagonal number
• 2484 - nonagonal number
• 2485 - triangular number
• 2491 - member of Ruth-Aaron pair with 2492 under second definition
• 2492 - member of Ruth-Aaron pair with 2491 under second definition
• 2500 - <math>50^2</math>
• 2501 - Mertens function zero
• 2502 - Mertens function zero
• 2510 - member of the Mian-Chowla sequence
• 2513 - member of the Padovan sequence
• 2517 - Mertens function zero
• 2519 - the smallest number when divided by 10 gives a remainder 9; when divided by 9 gives a remainder 8; when divided by 7 gives a remainder 6; and so on until when divided by 2 gives a remainder 1
• 2520 - highly composite number; smallest number divisible by numbers 1, 2, 3, 4, 5, 6, 7, 8, 9, 10, & 12 ; colossally abundant number; Harshad number in several bases.
• 2522 - Mertens function zero
• 2523 - Mertens function zero
• 2524 - Mertens function zero
• 2525 - Mertens function zero
• 2530 - Mertens function zero, Leyland number
• 2533 - Mertens function zero
• 2537 - Mertens function zero
• 2538 - Mertens function zero
• 2543 - Sophie Germain prime
• 2549 - Sophie Germain prime
• 2550 - pronic number
• 2552 - sum of the totient function for the first 91 integers
• 2556 - triangular number
• 2567 - Mertens function zero
• 2568 - Mertens function zero. Also number of digits in the decimal expansion of 1000!, or the product of all natural numbers from 1 to 1000.
• 2570 - Mertens function zero
• 2579 - safe prime
• 2580 - Keith number
• 2584 - Fibonacci number, sum of the first 37 primes
• 2596 - sum of the totient function for the first 92 integers
• 2600 - tetrahedral number, member of a Ruth-Aaron pair with 2601 (first definition)
  • 2600 Hz is the tone used by a blue box to defeat toll charges on long distance telephone calls.
  • 2600: The Hacker Quarterly is a magazine named after the above.
  • The Atari 2600 was a popular video game console.
• 2601 - <math>51^2</math>, member of a Ruth-Aaron pair with 2600 (first definition)
• 2620 - amicable number with 2924
• 2626 - decagonal number
• 2628 - triangular number
• 2632 - number of consecutive baseball games played by Cal Ripken, Jr.
• 2641 - centered pentagonal number
• 2647 - centered heptagonal number
• 2652 - pronic number
• 2656 - sum of the totient function for the first 93 integers
• 2674 - nonagonal number
• 2677 - balanced prime
• 2680 - number of 11-Queens Problem solutions
• 2689 - Mertens function zero, Proth prime
• 2693 - Sophie Germain prime
• 2699 - Sophie Germain prime
• 2701 - triangular number, super-Poulet number
• 2702 - sum of the totient function for the first 94 integers
• 2704 - <math>52^2</math>
• 2728 - Kaprekar number
• 2729 - highly cototient number
• 2731 - Wagstaff prime
• 2736 - octahedral number
• 2741 - Sophie Germain prime
• 2744 - <math>14^3</math>
• 2747 - sum of the first 38 primes
• 2753 - Sophie Germain prime, Proth prime
• 2756 - pronic number
• 2774 - sum of the totient function for the first 95 integers
• 2775 - triangular number
• 2780 - member of the Mian-Chowla sequence
• 2783 - member of a Ruth-Aaron pair with 2784 (first definition)
• 2784 - member of a Ruth-Aaron pair with 2783 (first definition)
• 2791 - cuban prime
• 2806 - centered pentagonal number, sum of the totient function for the first 96 integers
• 2809 - <math>53^2</math>, centered octagonal number
• 2819 - Sophie Germain prime, safe prime
• 2821 - Carmichael number
• 2835 - odd abundant number, decagonal number
• 2843 - centered heptagonal number
• 2850 - triangular number
• 2862 - pronic number
• 2870 - square pyramidal number
• 2871 - nonagonal number
• 2872 - tetranacci number
• 2879 - safe prime
• 2897 - Markov number
• 2902 - sum of the totient function for the first 97 integers
• 2903 - Sophie Germain prime, safe prime, balanced prime
• 2914 - sum of the first 39 primes
• 2916 - <math>54^2</math>
• 2924 - amicable number with 2620
• 2925 - magic constant of n×n normal magic square and n-Queens Problem for n = 18, tetrahedral number, member of the Mian-Chowla sequence
• 2926 - triangular number
• 2939 - Sophie Germain prime
• 2944 - sum of the totient function for the first 98 integers
• 2963 - Sophie Germain prime, safe prime, balanced prime
• 2965 - greater of 2nd pair of Smith brothers
• 2969 - Sophie Germain prime
• 2970 - harmonic divisor number, pronic number
• 2976 - centered pentagonal number
• 2997 - chiliagonal number
• 2999 - safe prime