13620
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 12
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 24
- Divisor Sum
- 38304
- Proper Divisor Sum (Aliquot Sum)
- 24684
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3616
- Möbius Function
- 0
- Radical
- 6810
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 4
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
- yes
- 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*(17*n + 1)/2.at n=40A022275
- Prime(n^2) +/- n are primes.at n=39A064495
- Maximal value of sum(p(i)p(i+1),i=1..n), where p(n+1)=p(1), as p ranges over all permutations of {1,2,...,n}.at n=33A110610
- Molecular topological indices of the cycle graphs.at n=29A192797
- Expansion of 1/(1-4*x+2*x^3+x^4).at n=7A195339
- Values of the difference d for 6 primes in geometric-arithmetic progression with the minimal sequence {7*7^j + j*d}, j = 0 to 5.at n=10A209205
- Triangle read by rows: T(n,k) = Sum_{j=k..n} binomial(n,j)*Stirling_2(j,k)*Bell(n-j), where Bell(n) = A000110(n), for n >= 1, 0 <= k <= n-1.at n=52A244489
- Number of active (ON, black) cells at stage 2^n-1 of the two-dimensional cellular automaton defined by "Rule 355", based on the 5-celled von Neumann neighborhood.at n=6A271398
- a(n) = 4*n*(n^2 + 2).at n=14A292022
- Numbers k such that Bernoulli number B_{k} has denominator 56786730.at n=1A295598
- Table read by rows: T(n,k) = number of k-sided polygons in an equal-armed cross with arms of length n (see Comments in A331456 for definition) for k = 3,4,5,6,7.at n=35A333037
- E.g.f. A(x) satisfies: A(x) = P(x)/Q(x) where P(x) = Sum_{n>=0} (n+1)*x^n*A(x)^(2*n)*exp(x*A(x)^n)/n! and Q(x) = Sum_{n>=0} x^n*A(x)^n*exp(x*A(x)^(n+1))/n!.at n=5A340939
- Numbers k such that 24*k-1 has at least three factors 7 and the partition function evaluated at k has at least the same number of factors 7 as 24*k-1.at n=16A340957
- Number of ways to write n as an ordered sum of 10 nonzero tetrahedral numbers.at n=43A341809
- Number of subsets of {1,2,...,n} such that no two elements differ by 1, 3, or 4.at n=27A351874
- Binary encoding of balanced ordered rooted trees (counted by A007059).at n=40A358524