256
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 9
- Divisor Sum
- 511
- Proper Divisor Sum (Aliquot Sum)
- 255
- 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
- 128
- Möbius Function
- 0
- Radical
- 2
- Omega Function (Ω)
- 8
- 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
- yes
- 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
- 8
- Smith Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- Prime Power
- yes
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- yes
- Achilles Number
- no
- Perfect Power
- yes
- Smooth Number
- yes
- Carmichael Number
- no
Classification
- Even
- yes
- Odd
- no
Names
- German
- zweihundertsechsundfünfzig· ordinal: zweihundertsechsundfünfzigste
- English
- two hundred fifty-six· ordinal: two hundred fifty-sixth
- Spanish
- doscientos cincuenta y seis· ordinal: 256º
- French
- deux cent cinquante-six· ordinal: deux cent cinquante-sixième
- Italian
- duecentocinquantasei· ordinal: 256º
- Latin
- ducenti quinquaginta sex· ordinal: 256.
- Portuguese
- duzentos e cinquenta e seis· ordinal: 256º
Appears in sequences
- Expansion of Product_{m >= 1} (1 + x^m); number of partitions of n into distinct parts; number of partitions of n into odd parts.at n=29A000009
- Number of ways of writing n as a sum of 4 squares; also theta series of four-dimensional cubic lattice Z^4.at n=21A000118
- Number of ways of writing n as a sum of 4 squares; also theta series of four-dimensional cubic lattice Z^4.at n=31A000118
- Maximal number of regions obtained by joining n points around a circle by straight lines. Also number of regions in 4-space formed by n-1 hyperplanes.at n=9A000127
- Generalized class numbers c_(n,1).at n=11A000233
- a(n) = a(n-1)*a(n-2) with a(0) = 1, a(1) = 2; also a(n) = 2^Fibonacci(n).at n=6A000301
- Powers of 4: a(n) = 4^n.at n=4A000302
- a(n) = n^n; number of labeled mappings from n points to themselves (endofunctions).at n=4A000312
- n followed by n^2.at n=31A000463
- Squares that are not the sum of 2 nonzero squares.at n=11A000548
- Numbers that are the sum of 2 squares but not sum of 3 nonzero squares.at n=25A000549
- Fourth powers: a(n) = n^4.at n=4A000583
- Moser-de Bruijn sequence: sums of distinct powers of 4.at n=16A000695
- Expansion of cos x (1 + sin x ) /cos 2x.at n=5A000825
- E.g.f. cos(x)/(cos(x) - sin(x)).at n=5A000828
- Jordan-Polya numbers: products of factorial numbers A000142.at n=20A001013
- Eighth powers: a(n) = n^8.at n=2A001016
- Powers of 16: a(n) = 16^n.at n=2A001025
- Numbers n such that the sum of the squares of n consecutive positive odd numbers x^2 + (x+2)^2 + ... + (x+2n-2)^2 = k^2 for some integer k. The least values of x and k for each n are in A056131 and A056132, respectively.at n=19A001033
- Triangle read by rows: T(n,k) = number of permutations of length n with exactly k rising or falling successions, for n >= 1, 0 <= k <= n-1.at n=17A001100