15156
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
- 18
- Divisor Sum
- 38402
- Proper Divisor Sum (Aliquot Sum)
- 23246
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5040
- Möbius Function
- 0
- Radical
- 2526
- Omega Function (Ω)
- 5
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 40
- 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
- Smallest composite which when sum of prime factors is repeatedly subtracted reaches a prime after n iterations.at n=27A053093
- Numbers which are the sum of their proper divisors containing the digit 5.at n=21A059464
- Sum of squares of first n quarter-squares (A002620).at n=16A059859
- Numbers m such that numerator of Sum_{k=1..m} 1/(prime(k)-k) is prime.at n=47A092065
- McKay-Thompson series of class 28B for the Monster group.at n=33A112169
- a(n) = (2*n^3 + 5*n^2 - 9*n)/2.at n=23A162258
- Number of 2 X 2 matrices having all elements in {-n,...,n} and determinant 1.at n=39A209982
- Number of k-element subsets S of {1,...,n} such that mean(S)<median(S).at n=14A212149
- Number of partitions p of n such that (number of numbers in p having multiplicity > 1) = number of 1s in p.at n=46A241090
- 26-gonal numbers: a(n) = n*(12*n-11).at n=36A255185
- Number of active (ON, black) cells at stage 2^n-1 of the two-dimensional cellular automaton defined by "Rule 267", based on the 5-celled von Neumann neighborhood.at n=6A271084
- Triangle read by rows: T(n,k) is the number of bargraphs of semiperimeter n having width k (n>=2, k>=1).at n=73A271942
- a(n) = A273059(4n+1).at n=21A275917
- 5th power analog of Keith numbers.at n=16A281916
- a(n) = sum_{k=0,...,[n/2]} |s(n-k,k)|^3, s = A048994, Stirling numbers of the first kind.at n=6A295228
- Numbers k such that Bernoulli number B_{k} has denominator 1919190.at n=9A295595
- Number of subset-sums of integer partitions of n.at n=21A304792
- G.f. A(x) satisfies: A(x) = (1/(1 - x)) * A(x^3)*A(x^5)*A(x^7)* ... *A(x^(2*k-1))* ...at n=54A308283
- Array read by ascending antidiagonals: T(n, k) is the number of n-core partitions with k corners.at n=58A355010