13856
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 27342
- Proper Divisor Sum (Aliquot Sum)
- 13486
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6912
- Möbius Function
- 0
- Radical
- 866
- Omega Function (Ω)
- 6
- 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
- no
- Pell Number
- no
- Tribonacci Number
- no
- Pronic Number
- no
Recreational
- Happy Number
- no
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 32
- Smith Number
- no
- Vampire Number
- 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
Classification
- Even
- yes
- Odd
- no
Appears in sequences
- a(n) = 1*t(n) + 2*t(n-1) + ... + k*t(n+1-k), where k=floor((n+1)/2) and t is A000201 (lower Wythoff sequence).at n=45A023866
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers), t = A000201 (lower Wythoff sequence).at n=44A024863
- Rounded total surface area of a regular icosahedron with edge length n.at n=40A071398
- Coefficient of q^2 in nu(n), where nu(0)=1, nu(1)=b and, for n>=2, nu(n)=b*nu(n-1)+lambda*(1+q+q^2+...+q^(n-2))*nu(n-2) with (b,lambda)=(2,2).at n=9A074359
- G.f.: 1 = Sum_{n>=0} a(n)*x^n*(1-x)/(1+x)^(2^n).at n=6A137160
- Indices where A138554 requires only squares < floor(sqrt(n))^2.at n=39A138555
- Number of binary strings of length n with equal numbers of 0001 and 1100 substrings.at n=15A164164
- Number of (w,x,y,z) with all terms in {0,...,n} and |w-x|=max{w,x,y,z}-min{w,x,y,z}.at n=15A212755
- Numbers n such that the sum of the numbers in the Collatz (3x+1) iteration of n is a perfect square.at n=33A225866
- Number of (n+1)X(2+1) arrays of permutations of 0..n*3+2 with each element having index change (+-,+-) 0,2 1,1 or 1,0.at n=3A263969
- T(n,k)=Number of (n+1)X(k+1) arrays of permutations of 0..(n+1)*(k+1)-1 with each element having index change (+-,+-) 0,2 1,1 or 1,0.at n=13A263973
- Number of (4+1)X(n+1) arrays of permutations of 0..n*5+4 with each element having index change (+-,+-) 0,2 1,1 or 1,0.at n=1A263976
- Expansion of Product_{k>=1} ((1 + x^k) * (1 + 3*x^k)).at n=17A266822
- Number of nX5 arrays of permutations of 5 copies of 0..n-1 with every element equal to or 1 greater than any west or northeast neighbors modulo n and the upper left element equal to 0.at n=6A267739
- Number of 7Xn arrays containing n copies of 0..7-1 with every element equal to or 1 greater than any west or northeast neighbors modulo 7 and the upper left element equal to 0.at n=4A267746
- G.f. A(x,y) satisfies: A(x,y) = x*y + A(x,x*y)^2, with A(0,y) = 1.at n=53A275670
- Triangle of number of 312-avoiding reduced valid hook configurations with n hooks that are on permutations with 2n + k points, for n=1 and 1<=k<=n.at n=27A338368
- Number of separable integer partitions of n without an alternating permutation.at n=60A345166