In the Epic of Gilgamesh, Utnapishtim is the man who survived the great flood in a boat.
Utnapishtim tells Gilgamesh that the god Ea warned him to build a boat and preserve living beings, craftsmen, and provisions. The flood story appears in Tablet XI of the standard Babylonian version of the epic. After the waters recede, Utnapishtim sends out birds to discover whether land has emerged.
The episode has notable parallels with the Genesis flood narrative, including divine warning, a large boat, survival of life, birds, and a landing after the waters subside. It is not identical to Genesis: the names of the hero and gods differ, and the surrounding theology and plot are distinct.
Utnapishtim is also called Atrahasis in related Mesopotamian traditions. That name should not be substituted casually, because the question specifically refers to the character in the Epic of Gilgamesh.