13639
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 14256
- Proper Divisor Sum (Aliquot Sum)
- 617
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 13024
- Möbius Function
- 1
- Radical
- 13639
- Omega Function (Ω)
- 2
- 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
- 76
- Smith Number
- yes
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
Appears in sequences
- Numbers that are the sum of 9 nonzero 8th powers.at n=21A003387
- Number of starting positions of Nim with 2n pieces such that 2nd player wins. Partitions of 2n such that xor-sum of partitions is 0.at n=24A048833
- a(n) = a(1) + a(2) + ... + a(n-1) - a(m) for n >= 4, where m = 2^(p+1) + 2 - n and p is the smallest integer such that 2^p < n - 1 <= 2^(p+1), starting with a(1) = 1, a(2) = 2, and a(3) = 3.at n=15A049909
- Moebius transform of A000011 (starting at term 0).at n=20A054183
- 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, 1), (-1, 0, 0), (0, 1, -1), (1, -1, -1), (1, 0, 1)}.at n=9A148781
- a(n) = n*(2*n^2 + 5*n + 13)/2.at n=23A163655
- a(n) = 4*a(n-1) - 9*a(n-2), with a(0)=0, a(1)=1.at n=11A190967
- Numbers of espalier polycubes of a given volume in dimension 4.at n=24A229917
- Zeroless numbers n with digits d_1, d_2, ... d_k such that d_1^3 + ... + d_k^3 is a cube.at n=51A254960
- a(n) = number of n-digit binary numbers in which the first k and last k digits have a Hamming distance of 1 or less, for all k from 1 to n.at n=44A288793
- a(0)=0, a(n) = 2*(a(n-1) + ceiling(n/2)) - 1 for n>0.at n=13A380384