15870
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
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 39816
- Proper Divisor Sum (Aliquot Sum)
- 23946
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4048
- Möbius Function
- 0
- Radical
- 690
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 4
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
- 128
- 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
- Convolution of (1, p(1), p(2), ...) and composite numbers.at n=25A023627
- Expansion of 1/((1-3x)(1-10x)(1-11x)(1-12x)).at n=3A028108
- Number of partitions of n into parts not of the form 11k, 11k+2 or 11k-2. Also number of partitions with 1 part of size 1 and differences between parts at distance 4 are greater than 1.at n=45A035945
- Numbers which have more different digits than their cubes.at n=4A061374
- Numbers k such that sopf(k) = sopf(k+2), where sopf(k) = A008472(k).at n=16A063968
- Number of squares (of another matrix) in M_2(n) - the ring of 2 X 2 matrices over Z_n.at n=17A068197
- Triangle, read by rows, equal to P^5, where triangle P = A135880.at n=41A135892
- 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, -1, 0), (-1, 0, 1), (0, 1, -1), (1, 0, 0)}.at n=11A148078
- a(n) = 36*n^2 - 6.at n=20A158462
- Number of nondecreasing strings of numbers x(i=1..7) in -n..n with sum x(i)^3 equal to 0.at n=26A188281
- Least number k such that n*k^n +/- 1 are twin primes, or a(n) = 0 if no such number exists.at n=43A239735
- a(n) = 30*n^2.at n=23A244636
- Least positive integer m with pi(m*n) = phi(m+n), where pi(.) is the prime-counting function and phi(.) is Euler's totient function.at n=10A247602
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 318", based on the 5-celled von Neumann neighborhood.at n=33A271252
- Sum of the third largest parts of the partitions of n into 9 squarefree parts.at n=51A326530