251

251 is a prime number. It is also a Sophie Germain prime because 2 x 251 + 1 = 503 is also prime.

251 is the smallest number that is the sum of three different cubes in two ways: 251 = 1³ + 5³ + 5³ = 2³ + 3³ + 6³.

251 can be expressed using the first three primes: 251 = 2³ + 3³.

251 is a divisor of 20⁵ - 1.


Telephone area code 251 covers southwestern Alabama.

Source: Prime Curios!