15924
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
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 37184
- Proper Divisor Sum (Aliquot Sum)
- 21260
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5304
- Möbius Function
- 0
- Radical
- 7962
- Omega Function (Ω)
- 4
- 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
- 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
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 84.at n=29A031582
- Indices of primes in sequence defined by A(0) = 73, A(n) = 10*A(n-1) - 7 for n > 0.at n=12A101134
- Numbers whose anti-divisors sum to a perfect cube.at n=24A109351
- Triangle T, read by rows, such that column 2k+1 of T equals column k of T^2 and column 2k of T equals column k of T*R: [T^2](n+k,k) = T(n+2k+1,2k+1) and [T*R](n+k,k) = T(n+2k,2k) for n>=0, k>=0, where R = SHIFT_RIGHT(T).at n=58A117418
- Column 3 of triangle A117418.at n=7A117421
- Triangle T, read by rows, equal to the matrix square of triangle A117418; also equals a column bisection of triangle A117418: column 2k+1 of T^(1/2) equals column k of T.at n=37A117427
- Number of partitions of n into distinct parts with boundary size 9.at n=33A227566
- Triangle read by rows: T(n,k) is the number of weighted lattice paths in B(n) having k returns to the horizontal axis (i.e., (1,-1)-steps ending on the horizontal axis). The members of B(n) are paths of weight n that start in (0,0), end on but never go below the horizontal axis, and whose steps are of the following four kinds: a (1,0)-step with weight 1; a (1,0)-step with weight 2; a (1,1)-step with weight 2; a (1,-1)-step with weight 1. The weight of a path is the sum of the weights of its steps.at n=54A246179
- Integers k such that A072473(k) = A072473(k+1) = A072473(k+2) = A072473(k+3).at n=2A255172
- Number of nX6 0..1 arrays with every element unequal to 0, 1 or 5 king-move adjacent elements, with upper left element zero.at n=10A303717
- a(n) = Sum_{i=1..n} sigma(i)*sigma(i+1), where sigma(n) = A000203(n) is the sum of the divisors of n.at n=25A330322