13508
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 25872
- Proper Divisor Sum (Aliquot Sum)
- 12364
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6120
- Möbius Function
- 0
- Radical
- 6754
- 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
- 37
- 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
- Ceiling of Gamma(n+1/5)/Gamma(1/5).at n=9A020130
- Numbers n such that Fibonacci(n) is not squarefree, but for all proper divisors k of n, Fibonacci(k) is squarefree.at n=30A065069
- a(1) = 2; a(n) = a(n-1)-th even nontotient number.at n=5A072415
- Expansion of (1-x)^(-1)/(1-2*x-2*x^2-x^3).at n=9A077845
- G.f. satisfies: A(x) = 1 + x*A(x) * A(x*A(x)) + x^2*A(x)^2 * A'(x*A(x)).at n=6A132070
- Number of unlabeled rooted trees with n nodes such that the minimal outdegree of inner nodes equals 7.at n=40A244461
- Solution of the complementary equation a(n) = a(n-1) + a(n-2) + b(n-2) + 2n, where a(0) = 1, a(1) = 3, b(0) = 2, b(1) = 4.at n=15A293350
- Numbers that are the sum of eight fourth powers in seven or more ways.at n=20A345582
- Numbers that are the sum of eight fourth powers in exactly seven ways.at n=19A345839
- Gaston Tarry's 1905 trimagic square of order 128, read by rows.at n=12A381002