13538
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 23232
- Proper Divisor Sum (Aliquot Sum)
- 9694
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5796
- Möbius Function
- -1
- Radical
- 13538
- 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
- 45
- Smith Number
- no
- Vampire 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
- yes
- Odd
- no
Appears in sequences
- Engel expansion of Sum_{k>=0} 1/(8 + k)^k.at n=11A063191
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, 0), (0, 0, -1), (1, 0, 1), (1, 1, 1)}.at n=7A150945
- Triangular array, T(n,k) = s(n,k) + s(n,n-k), where s(n,k) are the Stirling numbers of the first kind.at n=40A154843
- Triangle read by rows: T(n,k) = (n-1-k)*abs(s(n,n+1-k)), where s(n,k) are the signed Stirling numbers of the first kind and 1 <= k <= n.at n=32A199220
- Pell numbers (A000129) minus Lucas numbers beginning at 2 (A000032).at n=12A228748
- Number of n X n 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally or vertically, with no adjacent values equal.at n=4A232058
- Number of nX5 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally or vertically, with no adjacent values equal.at n=4A232062
- T(n,k)=Number of nXk 0..2 arrays with every 0 next to a 1 and every 1 next to a 2 horizontally or vertically, with no adjacent values equal.at n=40A232065
- Numbers n such that n^9+9 and n^9-9 are prime.at n=12A239505
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 126", based on the 5-celled von Neumann neighborhood.at n=35A270215
- G.f. A(x) satisfies: A(x) = 1 + x*A(x)^2 - x^2/A(x)^2.at n=10A295504
- Irregular table read by rows, T(n, k) is the rank of the k-th Seidel permutation of {1,...,n}, permutations sorted in lexicographical order.at n=24A347600
- a(n) = Sum_{k=3..n} binomial(k,3) * floor(n/k).at n=23A366971
- a(n) is the number of binary strings of length n which contain exactly one run of 1s of even length.at n=15A384497
- Triangle read by rows: T(n,k) = number of heapable permutations of length n that contain the max element on position k (positions starting from 0).at n=48A390546
- Triangle read by rows: T(n,k) is the number of binary strings of length n that contain exactly k runs of 1's of even length, 0 <= k <= floor((n+1)/3).at n=51A391669