Who are Noah/ Ziusudra/ Utnapishtim/ Atra-Hasis from The 12th Planet and what is their importance?

According to Sitchin, Enki gives one man, his servant, the foreknowledge to build a great boat and avoid dying in the Great Flood caused by the end of the last ice age. In myths, this man is known as Noah, Utnapishtim, or Atra-Hasis.