180

180 = 2² x 3² x 5.

180³ is the sum of consecutive cubes: 180³ = 6³ + 7³ + 8³ + . . . + 68³ + 69³.

180 has a representation as a sum of two squares: 180 = 6² + 12².

In the plane, the interior angles of a triangle add up to 180 degrees.

The number of Fahrenheit degrees between the freezing point of water, 32, and its boiling point, 212, is 180.

Source: Wells, D. 1997. The Penguin Dictionary of Curious and Interesting Numbers, rev. ed.