257

Sexy Prime (Primes p such that p + 6 is also prime)

257 = 1 + 2 + 34 × 5 + 67 + 8 + 9

257 = 9 + 8 + 76 + 54 × 3 + 2 × 1

257 = 0^6 + 1^8 + 2^4 − 3^9 + 4^7 + 5^5 + 6^1 + 7^3 + 8^2 + 9^0

257 = 1^2 + 16^2

257 = 1^4 + 4^4

257^2 = 32^2 + 255^2

257 divides 16^4 - 1.

Moser-de Bruijn sequence: sums of distinct powers of 4

Fermat prime: primes of the form 2^(2^k) + 1, k = 3

Quartan prime: primes of the form x^4 + y^4, × > 0, y > 0.

Numbers of edges of regular polygon constructible with unmarked straightedge and compass.

257 is an irregular prime, since it divides the numerator of the Bernoulli number B164.

Factors: 1, 257

Two hundred fifty-seven

Representations, Binary to Hexadecimal:

100000001_2
100112_3
10001_4
2012_5
1105_6
515_7
401_8
315_9
214_11
195_12
16a_13
145_14
122_15
101_16

<--- --->