251 (two hundred [and] fifty-one) is the natural number between 250 and 252. It is also a prime number.
In mathematics
251 is:
- a Sophie Germain prime.
- the sum of three consecutive primes (79 + 83 + 89) and seven consecutive primes (23 + 29 + 31 + 37 + 41 + 43 + 47).
- a Chen prime.
- an Eisenstein prime with no imaginary part.
- a de Polignac number, meaning that it is odd and cannot be formed by adding a power of two to a prime number.
- the first of four consecutive primes in an arithmetic progression, the common difference being 6: 251, 257, 263, 269.
- the smallest number that can be formed in more than one way by summing three positive cubes:
Every 5 × 5 matrix has exactly 251 square submatrices.
References