Samiksha Jaiswal (Editor)

257 (number)

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257
  
258 →

Prime
  
yes

Factorization
  
257

Roman numeral
  
CCLVII

Cardinal
  
two hundred fifty-seven

Ordinal
  
257th (two hundred and fifty-seventh)

257 (two hundred [and] fifty-seven) is the natural number following 256 and preceding 258.

Contents

In mathematics

257 is a prime number of the form 2 2 n + 1 , specifically with n = 3, and therefore a Fermat prime. Thus a regular polygon with 257 sides is constructible with compass and unmarked straightedge. It is currently the second largest known Fermat prime.

It is also a balanced prime, an irregular prime, a prime that is one more than a square, and a Jacobsthal–Lucas number.

There are exactly 257 combinatorially distinct convex polyhedra with eight vertices (or polyhedral graphs with eight nodes).

In other fields

  • The years 257 and 257 BC
  • 257 is the country calling code for Burundi. See List of country calling codes.
  • .257 Roberts, rifle cartridge
  • There is a Pac-Man themed restaurant called Level 257 located in Schaumburg, Illinois. It is in reference to the kill screen reached in Level 256 in the Pac-Man arcade game.

    • References

    257 (number) Wikipedia
    (Text) CC BY-SA