13640
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 14
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 32
- Divisor Sum
- 34560
- Proper Divisor Sum (Aliquot Sum)
- 20920
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4800
- Möbius Function
- 0
- Radical
- 3410
- Omega Function (Ω)
- 6
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 138
- 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) = Sum_{k=1..n-1} k*sigma(k)*sigma(n-k).at n=15A000441
- Number of permutations of [1,2,...,n] with n-1 inversions.at n=9A000707
- Sum of 10 nonzero 8th powers.at n=23A003388
- a(n) = floor(n*phi^15), where phi is the golden ratio, A001622.at n=10A004930
- a(n) = round(n*phi^15), where phi is the golden ratio, A001622.at n=10A004950
- a(n) = 2^n - n^3.at n=14A024013
- Smallest composite which when sum of prime factors is repeatedly subtracted reaches a prime after n iterations.at n=26A053093
- a(n) = lcm(n, n+1, n+2, n+3)/12.at n=29A067047
- Sums of terms of groups in A075626.at n=30A075629
- Triangle T(n,k) read by rows: see formula lines for definition.at n=16A097474
- Terms of A068563 that are not terms of A124240.at n=51A124241
- Terms of A061047 ending in 0.at n=22A146950
- Number of reduced words of length n in the Weyl group A_9.at n=9A161457
- Number of reduced words of length n in the Weyl group A_9.at n=36A161457
- Numbers m such that m and m+22 have the same sum of divisors.at n=41A172333
- The number of odd entries in all the 2-compositions of n.at n=7A181296
- T(n,k) = number of n-step one or two space at a time rook's tours on a k X k board summed over all starting positions.at n=40A187286
- Number of 5-step one or two space at a time rook's tours on an n X n board summed over all starting positions.at n=4A187290
- Multiples of 682.at n=20A200860
- a(n) = 2^n - n^k, where k is the largest integer such that 2^n >= n^k.at n=12A215892