15915
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 25488
- Proper Divisor Sum (Aliquot Sum)
- 9573
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8480
- Möbius Function
- -1
- Radical
- 15915
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 97
- 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
- no
- Odd
- yes
Appears in sequences
- Exponential reversion of rooted trees A000081.at n=8A050396
- Column 5 of array illustrated in A089574 and related to A034261.at n=8A107600
- Numbers k such that binomial(6k, k) - 1 is prime.at n=19A125244
- Number of lines through at least 2 points of a 7 X n grid of points.at n=38A160847
- Number of zero-sum -3..3 arrays of n elements with first through fourth differences also in -3..3.at n=11A201434
- Number of zero-sum -1..1 arrays of n elements with first through third differences also in -1..1.at n=29A202504
- Number of ordered triples (i,j,k) with |i|,|j|,|k|,|i*j*k| <= n and gcd(i,j,k) <= 1.at n=41A226357
- Number of integer partitions of n whose run-lengths are either weakly increasing or weakly decreasing.at n=40A332745
- Number of vertices in a complete bipartite graph where the n vertices of each part are placed on the vertices, and on opposite sides, of a regular 2n-gon.at n=16A392971