257 (number)
| ||||
|---|---|---|---|---|
| Cardinal | two hundred fifty-seven | |||
| Ordinal | 257th (two hundred fifty-seventh) | |||
| Factorization | prime | |||
| Prime | yes | |||
| Greek numeral | ΣΝΖ´ | |||
| Roman numeral | CCLVII | |||
| Binary | 1000000012 | |||
| Ternary | 1001123 | |||
| Senary | 11056 | |||
| Octal | 4018 | |||
| Duodecimal | 19512 | |||
| Hexadecimal | 10116 | |||
257 (two hundred [and] fifty-seven) is the natural number following 256 and preceding 258.
In mathematics
257 is a prime number of the form 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.[1]
It is also a balanced prime,[2] an irregular prime,[3] a prime that is one more than a square,[4] and a Jacobsthal–Lucas number.[5]
There are exactly 257 combinatorially distinct convex polyhedra with eight vertices (or polyhedral graphs with eight nodes).[6]
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.
- 257ers is a German hip hop duo
References
- ^ Hsiung, C. Y. (1995), Elementary Theory of Numbers, Allied Publishers, pp. 39–40, ISBN 9788170234647.
- ^ Sloane, N. J. A. (ed.). "Sequence A006562 (Balanced primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Sloane, N. J. A. (ed.). "Sequence A000928 (Irregular primes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Sloane, N. J. A. (ed.). "Sequence A002496 (Primes of form n^2 + 1)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Sloane, N. J. A. (ed.). "Sequence A014551 (Jacobsthal-Lucas numbers)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.
- ^ Sloane, N. J. A. (ed.). "Sequence A000944 (Number of polyhedra (or 3-connected simple planar graphs) with n nodes)". The On-Line Encyclopedia of Integer Sequences. OEIS Foundation.