15539
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 15960
- Proper Divisor Sum (Aliquot Sum)
- 421
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 15120
- Möbius Function
- 1
- Radical
- 15539
- Omega Function (Ω)
- 2
- 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
- 115
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- Squarefree Number
- yes
- 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
- no
- Odd
- yes
Appears in sequences
- A Chebyshev transform of A099453 associated to the knot 8_12.at n=6A099454
- Number of orbits of the 5-step recursion mod n.at n=26A106287
- a(n) = A007290(n+2) - 1 = 2*C(n+2,3) - 1.at n=35A108766
- Expansion of -x*(8*x^2-4*x+1) / ((2*x-1)*(4*x^2-x+1)).at n=13A112260
- The 4k+3 integers corresponding to the record positions in A165601.at n=37A166046
- Odd nonprimes n such that n+d+1 is prime for all divisors d of n.at n=31A187554
- Integers m such that phi(sigma(k))/sigma(phi(k)) > phi(sigma(m))/sigma(phi(m)) for all k<m.at n=15A227011
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 294", based on the 5-celled von Neumann neighborhood.at n=44A271134
- Number of (binary) max-heaps on n elements from the set {0,1} containing exactly four 0's.at n=48A326505
- a(n) = A342068(10^n).at n=14A342852
- For 1<=x<=n, 1<=y<=n, write gcd(x,y) = u*x+v*y with u,v minimal; a(n) = sum of the values of u^2+v^2.at n=24A345434
- Number of ordered n-tuples (x_1, x_2, x_3, ..., x_n) such that Sum_{k=1..n} k/x_k is an integer and x_k is an integer between 1 and n for 1 <= k <= n.at n=7A349145
- a(n) = (1/4)*A357287(n).at n=22A357288