255
domain: N
Properties
Digital Properties
- Digit Count
- 3
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 432
- Proper Divisor Sum (Aliquot Sum)
- 177
- 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
- -1
- Radical
- 255
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 3
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
- 47
- Smith Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- Prime Power
- no
- Prime Factorization
- no
- Twin Prime
- no
- Mersenne Prime
- no
- Sophie Germain Prime
- no
- Safe Prime
- no
- Powerful Number
- no
- Achilles Number
- no
- Perfect Power
- no
- Smooth Number
- no
- Carmichael Number
- no
Classification
- Even
- no
- Odd
- yes
Names
- German
- zweihundertfünfundfünfzig· ordinal: zweihundertfünfundfünfzigste
- English
- two hundred fifty-five· ordinal: two hundred fifty-fifth
- Spanish
- doscientos cincuenta y cinco· ordinal: 255º
- French
- deux cent cinquante-cinq· ordinal: deux cent cinquante-cinqième
- Italian
- duecentocinquantacinque· ordinal: 255º
- Latin
- ducenti quinquaginta quinque· ordinal: 255.
- Portuguese
- duzentos e cinquenta e cinco· ordinal: 255º
Appears in sequences
- a(n) = 2^n - 1. (Sometimes called Mersenne numbers, although that name is usually reserved for A001348.)at n=8A000225
- a(n) = 4*n^2 - 1.at n=8A000466
- Expansion of Product_{k>=0} (1 + x^(2k+1)); number of partitions of n into distinct odd parts; number of self-conjugate partitions; number of symmetric Ferrers graphs with n nodes.at n=63A000700
- Numbers that are divisible by at least three different primes.at n=43A000977
- Dimensions (sorted, with duplicates removed) of real simple Lie algebras.at n=54A001066
- Length of one version of Kolakoski sequence {A000002(i)} at n-th growth stage.at n=14A001083
- Double-bitters: only even length runs in binary expansion.at n=15A001196
- Numbers k such that phi(k) = phi(k+1).at n=6A001274
- Expansion of 1/(1-x)^2/(1-x^2)/(1-x^4)/(1-x^10)/(1-x^20).at n=18A001307
- Sierpiński's triangle (Pascal's triangle mod 2) converted to decimal.at n=7A001317
- Number of partitions of n into at most 5 parts.at n=22A001401
- Sorting numbers: number of comparisons for merge insertion sort of n elements.at n=55A001768
- Sorting numbers: maximal number of comparisons for sorting n elements by binary insertion.at n=52A001855
- Denominators of cosecant numbers: -2*(2^(2*n-1)-1)*Bernoulli(2*n).at n=16A001897
- Denominators of cosecant numbers: -2*(2^(2*n-1)-1)*Bernoulli(2*n).at n=8A001897
- Denominators of cosecant numbers: -2*(2^(2*n-1)-1)*Bernoulli(2*n).at n=32A001897
- v-pile positions of the 4-Wythoff game with i=3.at n=48A001968
- Numbers dividing A002037(i) and larger than A002037(i-1), for some i>0.at n=21A002038
- Least number k such that phi(k) = m, where m runs through the values (A002202) taken by phi.at n=47A002181
- ((2^m - 1) / p) mod p, where p = prime(n) and m = ord(2,p).at n=53A002323