105 (number)

105 (one hundred [and] five) is the natural number following 104 and preceding 106.

← 100 101 102 103 104 105 106 107 108 109 → List of numbers — Integers ← 100 110 120 130 140 150 160 170 180 190 →
Cardinal	one hundred [and] five
Ordinal	105th (one hundred [and] fifth)
Factorization	<math>3 \cdot 5 \cdot 7</math>
Divisors	1, 3, 5, 7, 15, 21, 35, 105
Roman numeral	CV
Binary	1101001
Hexadecimal	69

Contents 1 In mathematics 2 In science 3 In other fields 4 In the space program 5 In sports 6 See also 7 References

In mathematics

105 is the double factorial of 7. 105 is a triangular number and a 12-gonal number as well as a sphenic number and a Zeisel number. It comes in the middle of the prime quadruplet (101, 103, 107, 109). The only other such odd numbers less than a thousand are 15, 195 and 825. 105 is also a pseudoprime to the prime bases: 13, 29, 41, 43, 71, 83 and 97. The distinct prime factors of 105 add up to 15, and so do the ones of 104, hence the two numbers form a Ruth-Aaron pair under the first definition. One hundred five is also a number n for which <math>n - 2^k</math> is prime, for <math>k < log_2(n)</math>. (This even works up to <math>k = 8</math>, ignoring the negative sign.) 105 is the sum of the first five square pyramidal numbers. 105 is the smallest integer such that the factorization of <math>x^n-1</math> over Q includes coefficients other than <math>\pm 1</math>.

In science

• The atomic number of hahnium, also known as dubnium.

In astronomy,

Messier object M105, a magnitude 11.0 elliptical galaxy in the constellation Leo

The New General Catalogue object NGC105, a magnitude 13.2 spiral galaxy in the constellation Pisces

Asteroid 105 Artemis

The Saros number of the solar eclipse series which began on 499 March 27 and ended on 1779 May 16. The duration of Saros series 105 was 1280.1 years, and it contained 72 solar eclipses.

The Saros number of the lunar eclipse series which began on 566 August 16 and ended on 1882 October 26. The duration of Saros series 105 was 1316.2 years, and it contained 74 lunar eclipses.

In other fields

105 is also:

• The year AD 105 or 105 BC.
• The designation of some spur routes of Interstate 5.
• A film format introduced by Kodak for their first folding camera. See 120 film.
• The name of a song on Smash Mouth's Get the Picture? CD (2003)
• The name of a road bicycle groupset from Shimano.
• The number of surat al-Fil in the Qur'an.
• The prison cell where Doctor Manette lived, in Charles Dickens's "A Tale of Two Cities"
• Radio stations such as Power 105 WWPR-FM, New York City, and J105 KJOT, Boise, Idaho
• The 105th United States Congress met from January 3, 1997 to January 3, 1999, during Bill Clinton administration
• The Republic F-105 Thunderchief, commonly known as the "Thud" by its crews, was a single-seat supersonic fighter-bomber used by the United States Air Force
• The USS Pioneer (AM-105) was a U.S. Navy Auk class minesweeper during WWII
• Bo 105 is a light, twin-engine, multi-purpose utility helicopter developed in 1991
• The police emergency telephone number in Peru
• PT 105 was a US Navy PT boat in WWII commanded by Dick Keresey, which fought in the same battle as PT 109
• East 105th–Quincy is a station on the RTA Rapid Transit Red Line in Cleveland, Ohio

In the space program

• A-105 was the third flight of an operational Saturn I, which launched July 30, 1965
• The Space Shuttle mission STS-105 of the Space Shuttle Discovery launched August 10, 2001
• The Orbiter Vehicle Designation OV-105 for Shuttle Endeavour

In sports

• The 105th Kentucky Derby won by Spectacular Bid on May 5, 1979
• The 105th Boston Marathon won by Lee Bong-Ju on April 16, 2001
• The 105th Army-Navy Game won by Navy (42-13) at Philadelphia's Lincoln Financial Field on December 4, 2004

See also

• List of highways numbered 105

References

• Wells, D. The Penguin Dictionary of Curious and Interesting Numbers London: Penguin Group. (1987): 134