181

181 is a prime number.

181 can be represented as the sum of two squares: 9² + 10² = 181.

181 is the hypotenuse of a primitive Pythagorean triple: 181² = 19² + 180².


181 is a centered square number.


Rusty Romeos was the 181st short film starring the Three Stooges, released October 17, 1957.

Source: Wikipedia