15981
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 24384
- Proper Divisor Sum (Aliquot Sum)
- 8403
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9120
- Möbius Function
- -1
- Radical
- 15981
- 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
- 84
- Smith Number
- yes
- 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
- 4-dimensional centered tetrahedral numbers.at n=16A008498
- a(0) = 1, a(n) = 19*n^2 + 2 for n>0.at n=29A010009
- Number of inequivalent n-state 1-input n-output automata.at n=5A054748
- Number of 3 x n binary matrices without unit columns up to row and column permutations.at n=35A057524
- Hyper-Wiener index of a benzenoid consisting of a zig-zag chain of n hexagons (s=13; see the Gutman et al. reference).at n=7A193394
- The consecutive squares of numbers multiplied by their next consecutive integer.at n=18A193608
- Triangle of coefficients of polynomials u(n,x) jointly generated with A209142; see the Formula section.at n=50A209141
- Triangle of coefficients of polynomials u(n,x) jointly generated with A209746; see the Formula section.at n=49A209745
- Number of partitions of n into 6 parts such that every i-th smallest part (counted with multiplicity) is different from i.at n=44A244242
- Numbers k such that (32*10^k - 77)/9 is prime.at n=18A290153
- Numbers k such that A361338(k) = 9.at n=27A361348
- a(n) = Sum_{k=0..n} binomial(4*n+k,n).at n=4A391542