13240
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 10
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 29880
- Proper Divisor Sum (Aliquot Sum)
- 16640
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 5280
- Möbius Function
- 0
- Radical
- 3310
- Omega Function (Ω)
- 5
- 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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 45
- 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
- Number of polyaboloes (or polytans): number of different shapes that can be formed with n congruent isosceles right triangles, identifying mirror images.at n=9A006074
- Number of ordered quadruples of integers from [ 2,n ] with no global factor.at n=22A015638
- a(n) = Sum_{j=0..floor(n/2)} T(2*j + q), where T(n) are generalized tribonacci numbers (A001644) and q = n - 2*floor(n/2).at n=15A074475
- a(n) = A004061(n) - 1.at n=12A086123
- Fourth diagonal (m=3) of triangle A084938; a(n) = A084938(n+3,n) = (n^3 + 9*n^2 + 26*n)/6.at n=40A092286
- Numbers k such that k + sigma(k) + phi(k) is a square.at n=20A116009
- Numbers of isomers of unbranched a-4-catapolypentagons - see Brunvoll reference for precise definition.at n=11A121134
- Expansion of eta(q^4) * eta(q^28) / (eta(q) * eta(q^7)) in powers of q.at n=38A123648
- Those positive integers n where, when written in binary, there are exactly k number of runs (of either 0's or 1's) each of exactly k length, for all k where 1<=k<=m, for some positive integer m.at n=29A175356
- Floor(1/{(9+n^4)^(1/4)}), where {} = fractional part.at n=30A184633
- Numbers whose digits are a permutation of (0,...,m) for some m.at n=39A199168
- Numbers such that Liouville's function (A002819) and the little omega analog to Liouville's function (A174863) are equal.at n=45A224987
- Let an integer with k+1 digits as n = d(k)*10^k + d(k-1)*10^(k-1) + ... + d(0)*10^0 and consider the transform T(n) = k*10^d(k) + (k-1)*10^d(k-1) + ... + 0*10^d(0). a(n) gives the fixed points of the transform T(n).at n=18A226767
- Number of binary words of length n with exactly 4 (possibly overlapping) occurrences of the subword given by the binary expansion of n.at n=14A236233
- The chalcogen sequence (a(n) = A018227(n)-2).at n=39A271994
- Products of distinct numbers in A052963.at n=37A274453
- Starting with a(1) = 0, a(2) = 1, a(n) = smallest nonnegative integer that shares all digits with previous terms. No repeated digits are allowed.at n=40A297062
- Coordination sequence for "tea" 3D uniform tiling.at n=41A299285
- a(1) = 1; a(n+1) is the smallest k > a(n) such that 2^k == 2^a(n) (mod a(n)).at n=43A306829
- A(n, k) = Stirling2(n + k, k)*A053657(n)*k!/(n + k)!, array read by ascending antidiagonals for n >= 0 and k >= 0.at n=50A325146