56
domain: N
Properties
Digital Properties
- Digit Count
- 2
- Digit Sum
- 11
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 120
- Proper Divisor Sum (Aliquot Sum)
- 64
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 24
- Möbius Function
- 0
- Radical
- 14
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 2
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
- yes
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- yes
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 19
- Smith Number
- no
Classification
- Natural
- yes
- Even
- yes
- Odd
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
Names
- German
- sechsundfünfzig· ordinal: sechsundfünfzigste
- English
- fifty-six· ordinal: fifty-sixth
- Spanish
- cincuenta y seis· ordinal: 56º
- French
- cinquante-six· ordinal: cinquante-sixième
- Italian
- cinquantasei· ordinal: 56º
- Latin
- quinquaginta sex· ordinal: 56.
- Portuguese
- cinquenta e seis· ordinal: 56º
Appears in sequences
- Definition (1): Number of n-bead binary necklaces with beads of 2 colors where the colors may be swapped but turning over is not allowed.at n=10A000013
- The positive integers. Also called the natural numbers, the whole numbers or the counting numbers, but these terms are ambiguous.at n=55A000027
- Let k = p_1^e_1 p_2^e_2 p_3^e_3 ... be the prime factorization of n. Sequence gives k such that the sum of the numbers of 1's in the binary expansions of e_1, e_2, e_3, ... is odd.at n=26A000028
- Numbers that are not squares (or, the nonsquares).at n=48A000037
- a(n) is the number of partitions of n (the partition numbers).at n=11A000041
- 1-digit numbers arranged in alphabetical order, then the 2-digit numbers arranged in alphabetical order, then the 3-digit numbers, etc.at n=30A000052
- Numbers k such that k^4 + 1 is prime.at n=12A000068
- Odious numbers: numbers with an odd number of 1's in their binary expansion.at n=28A000069
- Tetranacci numbers: a(n) = a(n-1) + a(n-2) + a(n-3) + a(n-4) for n >= 4 with a(0) = a(1) = a(2) = 0 and a(3) = 1.at n=10A000078
- a(n) = n^2*Product_{p|n} (1 + 1/p).at n=6A000082
- Number of transformation groups of order n.at n=38A000113
- Number of transformation groups of order n.at n=48A000113
- Number of even sequences with period 2n (bisection of A000013).at n=5A000116
- Central polygonal numbers (the Lazy Caterer's sequence): n(n+1)/2 + 1; or, maximal number of pieces formed when slicing a pancake with n cuts.at n=10A000124
- Positive zeros of Bessel function of order 0 rounded to nearest integer.at n=17A000134
- From von Staudt-Clausen representation of Bernoulli numbers: a(n) = Bernoulli(2n) + Sum_{(p-1)|2n} 1/p.at n=8A000146
- The Franel number a(n) = Sum_{k = 0..n} binomial(n,k)^3.at n=3A000172
- Lower Wythoff sequence (a Beatty sequence): a(n) = floor(n*phi), where phi = (1+sqrt(5))/2 = A001622.at n=34A000201
- a(8i+j) = 13i + a(j), where 1<=j<=8.at n=34A000202
- a(n) = sigma(n), the sum of the divisors of n. Also called sigma_1(n).at n=27A000203