251 (number)

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← 250 251 252 →
Cardinal two hundred fifty-one
Ordinal 251st
(two hundred fifty-first)
Factorization prime
Prime 54th
Greek numeral ΣΝΑ´
Roman numeral CCLI
Binary 111110112
Ternary 1000223
Quaternary 33234
Quinary 20015
Senary 10556
Octal 3738
Duodecimal 18B12
Hexadecimal FB16
Vigesimal CB20
Base 36 6Z36

251 (two hundred [and] fifty-one) is the natural number between 250 and 252. It is also a prime number.

In mathematics[edit]

251 is:

  • a Sophie Germain prime.[1]
  • 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.[2][3]
  • the smallest number that can be formed in more than one way by summing three positive cubes:[4][5]

Every 5 × 5 matrix has exactly 251 square submatrices.[6]

References[edit]