15912
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 48
- Divisor Sum
- 49140
- Proper Divisor Sum (Aliquot Sum)
- 33228
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4608
- Möbius Function
- 0
- Radical
- 1326
- Omega Function (Ω)
- 7
- 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
- no
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 27
- 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
- Alkane (or paraffin) numbers l(10,n).at n=11A018211
- Numerator of n*(n-2)*(2*n-1)/(2*(n-1)).at n=24A022997
- a(n) = ((n+3)!/2)*Sum_{k=1..n} (-1)^(k+1)/(k+3).at n=5A024189
- a(n) = n*(n + 1)*(3*n + 1).at n=17A027903
- Least term in period of continued fraction for sqrt(n) is 7.at n=25A031431
- Number of reversible strings with n-1 beads of 2 colors. 7 beads are black. String is not palindromic.at n=10A032094
- a(n) = a(n-1) + a(round(2*(n-1)/3)) + a(round((n-1)/3)) with a(1)=1, a(2)=2.at n=35A033500
- Number of partitions in parts not of the form 25k, 25k+1 or 25k-1. Also number of partitions with no part of size 1 and differences between parts at distance 11 are greater than 1.at n=45A036000
- a(n) = LCM(binomial(n,0), ..., binomial(n,n)) / binomial(n,floor(n/2)).at n=36A048619
- (Terms in A014476)/2.at n=39A051497
- a(n) = ((8*n+10)(!^8))/20, related to A034908 ((8*n+2)(!^8) octo- or 8-factorials).at n=3A053115
- Numbers k such that sigma(x) = k has exactly 9 solutions.at n=36A060665
- Twelfth column of Losanitsch's triangle A034851 (formatted as lower triangular matrix).at n=7A062136
- a(n) = lcm{1, ..., 2n} / binomial(2n, n).at n=18A068550
- Numbers k such that phi(k) = 2*tau(k)^2.at n=22A068564
- Normalized triangle of odd numbered entries of even numbered rows of Pascal's triangle A007318.at n=41A091043
- Normalized triangle of odd numbered entries of even numbered rows of Pascal's triangle A007318.at n=39A091043
- One half of odd-numbered entries of even-numbered rows of Pascal's triangle A007318.at n=41A091044
- One half of odd-numbered entries of even-numbered rows of Pascal's triangle A007318.at n=39A091044
- Numbers n such that primitive solutions for 1/n^2 = 1/x^2 + 1/y^2 exist.at n=38A094807