251 (number)

Template:Infobox number 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 smallest number that can be formed in more than one way by summing three positive cubes:$251=2^3+3^3+6^3=1^3+5^3+5^3.$

Every 5 × 5 matrix has exactly 251 square submatrices.

References

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