13216
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
- 24
- Divisor Sum
- 30240
- Proper Divisor Sum (Aliquot Sum)
- 17024
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5568
- Möbius Function
- 0
- Radical
- 826
- Omega Function (Ω)
- 7
- 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
- 94
- 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) = [ a(n-1)/a(1) ] + [ a(n-2)/a(2) ] + ... + [ a(1)/a(n-1) ], for n >= 3.at n=21A022864
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 57.at n=32A031555
- A simple grammar: power set of pairs of sequences.at n=23A052812
- At stage 1, start with a unit equilateral equiangular triangle. At each successive stage add 3*(n-1) new triangles around outside with edge-to-edge contacts. Sequence gives number of triangles (regardless of size) at n-th stage.at n=30A064412
- Sum of the digits of the n-th Mersenne prime (A000668).at n=20A066538
- a(n) = A000094(n+4) - A006918(n).at n=31A084835
- Structured triakis octahedral numbers (vertex structure 4).at n=15A100171
- Number of permutations of floor(i*9/5), i=0..n-1, with all sums of two and three adjacent terms respectively unique.at n=7A147898
- Number of permutations of floor(i*9/5), i=0..n-1, with all sums of 2 through 4 adjacent terms respectively unique.at n=7A147906
- Number of permutations of floor(i*9/5), i=0..n-1, with all sums of 2 through 5 adjacent terms respectively unique.at n=7A147915
- Number of length 3+2 0..n arrays with some pair in every consecutive three terms totalling exactly n.at n=12A245872
- a(n) is the smallest nonnegative integer such that a(n)! contains a string of exactly n consecutive 9's.at n=8A254717
- a(n) = number of steps to reach 0 when starting from k = n^3 and repeatedly applying the map that replaces k with k - A055401(k), where A055401(k) = the number of positive cubes needed to sum to k using the greedy algorithm.at n=48A261227
- Number of length-n 0..6 arrays with no following elements larger than the first repeated value.at n=4A267469
- T(n,k)=Number of length-n 0..k arrays with no following elements larger than the first repeated value.at n=49A267471
- Number of length-5 0..n arrays with no following elements larger than the first repeated value.at n=5A267473
- Number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 275", based on the 5-celled von Neumann neighborhood.at n=57A271091
- Growth series for group with presentation < S, T : S^3 = T^3 = (S*T)^6 = 1 >.at n=13A298807
- Growth series for group with presentation < S, T : S^2 = T^3 = (S*T)^12 = 1 >.at n=26A299253
- Expansion of Product_{k>=1} (1 + x^prime(k))/(1 - x^prime(k)).at n=50A300413