13612
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 24696
- Proper Divisor Sum (Aliquot Sum)
- 11084
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6560
- Möbius Function
- 0
- Radical
- 6806
- 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
- 63
- 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
- a(n) = (n+2)*2^(2*n-1) - (n/2)*binomial(2*n,n).at n=6A003583
- a(n) = 4*n*(2*n + 1).at n=41A033586
- Column 8 of triangle A055907.at n=5A055914
- Sum of next n composite numbers.at n=27A072475
- Number of primitive roots modulo prime(n)^2, where prime(n) is n-th prime.at n=38A104039
- 2n^4+6n^2+4 = 2(n^2+1)(n^2+2).at n=8A120571
- Numbers k such that k^2 divides 9^k - 1.at n=34A127101
- Numbers k such that k^3 divides 3^(k^2) - 1.at n=35A129211
- Number of maximal directed trails in the labeled n-ladder graph P_2 X P_n.at n=42A135443
- E.g.f. A(x) satisfies: A( Integral 1/A(x)^3 dx ) = exp(x).at n=5A259822
- Number of active (ON, black) cells at stage 2^n-1 of the two-dimensional cellular automaton defined by "Rule 361", based on the 5-celled von Neumann neighborhood.at n=6A271415
- Least common multiple of 5*n+1 and 5*n-1.at n=33A282285
- Numbers k such that (19*10^k + 149)/3 is prime.at n=19A285938
- Ordered perimeters p of primitive Pythagorean triangles no side of which is squarefree.at n=23A329392