15536
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 10
- Divisor Sum
- 30132
- Proper Divisor Sum (Aliquot Sum)
- 14596
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7760
- Möbius Function
- 0
- Radical
- 1942
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 2
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
- 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
- Discriminants of quintic fields with 2 complex conjugates (negated).at n=24A023684
- Let (u1,u2) be successive untouchable numbers such that phi(u1) = phi(u2); sequence gives values of u2.at n=32A048190
- Numerators of successive partial sums of sum(1/(2^n-1)).at n=5A087689
- Number of strings of length n, using as symbols numbers from the set {1, 2, ..., n}, in which consecutive symbols differ by exactly 1.at n=12A102699
- Number of zig-zag paths from top to bottom of a rectangle of width 12 with n rows.at n=11A153361
- G.f. satisfies: x = A(x) - A(x)^2 - A(A(x))^2.at n=5A177409
- Numbers k such that there is 1 prime between 100*k and 100*k + 99.at n=13A186393
- Number of -2..2 arrays x(i) of n+1 elements i=1..n+1 with x(i)+x(j), x(i+1)+x(j+1), -(x(i)+x(j+1)), and -(x(i+1)+x(j)) having three or four distinct values for every i<=n and j<=n.at n=5A211463
- Number of (w,x,y,z) with all terms in {1,...,n} and |w-x|>|x-y|+|y-z|.at n=17A212573
- a(n) = lcm_{d|n} sigma(d) * Sum_{d|n} 1/sigma(d), where sigma(d) represents the sum of divisors of d (A000203(d)).at n=31A265708
- a(n) = numerator of Sum_{d|n} 1/sigma(d).at n=31A265709
- Number of ways to move elements of an nXnXn triangular array to themselves or a neighbor, with no 2-cycles and with no more than 5-1 elements moved to themselves.at n=4A271849
- T(n,k)=Number of ways to move elements of an nXnXn triangular array to themselves or a neighbor, with no 2-cycles and with no more than k-1 elements moved to themselves.at n=40A271852
- p-INVERT of (1,0,0,1,0,0,0,0,0,0,...), where p(S) = 1 - S^4.at n=34A292404
- Even integers k such that lambda(sum of even divisors of k) = sum of odd divisors of k.at n=26A293356
- Maximal Laman number among all minimally rigid graphs on n vertices.at n=12A306420
- Number of integer partitions of n having a permutation with all equal run-lengths.at n=37A383013