257
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 2
- Divisor Sum
- 258
- Proper Divisor Sum (Aliquot Sum)
- 1
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 256
- Möbius Function
- -1
- Radical
- 257
- Omega Function (Ω)
- 1
- Little Omega Function (ω)
- 1
Special
- Factorial
- no
- Catalan Number
- no
- Bell Number
- no
- Motzkin Number
- no
- Primorial
- no
Figurate Numbers
- Fibonacci Number
- no
- Triangular Number
- no
- Perfect Square
- no
- Perfect Cube
- no
- Pentagonal Number
- no
- Hexagonal Number
- no
- Lucas Number
- no
- Tetrahedral Number
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 122
- Smith Number
- no
Primality
- Prime
- yes
- Composite Number
- no
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Prime Index
- 55
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Names
- German
- zweihundertsiebenundfünfzig· ordinal: zweihundertsiebenundfünfzigste
- English
- two hundred fifty-seven· ordinal: two hundred fifty-seventh
- Spanish
- doscientos cincuenta y siete· ordinal: 257º
- French
- deux cent cinquante-sept· ordinal: deux cent cinquante-septième
- Italian
- duecentocinquantasette· ordinal: 257º
- Latin
- ducenti quinquaginta septem· ordinal: 257.
- Portuguese
- duzentos e cinquenta e sete· ordinal: 257º
Appears in sequences
- a(n) = 2^n + 1.at n=8A000051
- Number of positive integers <= 2^n of form x^2 + 6 y^2.at n=10A000077
- Fermat numbers: a(n) = 2^(2^n) + 1.at n=3A000215
- Number of bipartite partitions of n white objects and 3 black ones.at n=7A000412
- Sum of 8th powers: 1^8 + 2^8 + ... + n^8.at n=2A000542
- Expansion of exp(-x) / (1 - exp(x) + exp(-x)).at n=4A000556
- Number of points of norm <= n in cubic lattice.at n=4A000605
- Moser-de Bruijn sequence: sums of distinct powers of 4.at n=17A000695
- Irregular primes: primes p such that at least one of the numerators of the Bernoulli numbers B_2, B_4, ..., B_{p-3} (A000367) is divisible by p.at n=9A000928
- Genus of complete graph on n nodes.at n=58A000933
- Number of polyhedra (or 3-connected simple planar graphs) with n nodes.at n=7A000944
- a(n) = least m such that if a/b < c/d where a,b,c,d are integers in [0,n], then a/b < k/m < c/d for some integer k.at n=19A001000
- Primes with 3 as smallest primitive root.at n=12A001123
- Primes == +-1 (mod 8).at n=24A001132
- A sequence of sorted odd primes 3 = p_1 < p_2 < ... < p_m such that p_i-2 divides the product p_1*p_2*...*p_(i-1) of the earlier primes and each prime factor of p_i-1 is a prime factor of twice the product.at n=8A001259
- Table T(n,k) in which n-th row lists prime factors of 2^n - 1 (n >= 2), with repetition.at n=34A001265
- Table T(n,k) in which n-th row lists prime factors of 2^n + 1 (n >= 0), with repetition.at n=12A001269
- Table T(n,k) in which n-th row lists prime factors of 2^n + 1 (n >= 0), with repetition.at n=54A001269
- Sierpiński's triangle (Pascal's triangle mod 2) converted to decimal.at n=8A001317
- A generalized Fibonacci sequence.at n=33A001584