17640
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 18
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 72
- Divisor Sum
- 66690
- Proper Divisor Sum (Aliquot Sum)
- 49050
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4032
- Möbius Function
- 0
- Radical
- 210
- Omega Function (Ω)
- 8
- 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
- 48
- 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) = C(3n,n) - C(2n,n).at n=6A000846
- Number of 5-dimensional centered tetrahedral numbers.at n=12A008499
- a(n) = A027113(n, 2n-7).at n=8A027125
- a(n) = (2*n+1)*(9*n+1).at n=31A033573
- Number of possible rook moves on an n X n chessboard.at n=20A035006
- For all n, if d is recursively applied to a(n) exactly 6 times then the fixed point of d-iteration is just reached.at n=23A036458
- Number of partitions satisfying (cn(0,5) <= cn(1,5) = cn(4,5)).at n=52A036809
- Theta series of lattice A_2 tensor A_15+ (dimension 30, det 3^15, min. norm 4).at n=3A037212
- Unitary-sigma sigma multiply perfect numbers: numbers k such that A061765(k) = m*k for some integer m.at n=36A045795
- Triangle read by rows, the Bell transform of n!*binomial(4,n) (without column 0).at n=24A049424
- Expansion of e.g.f.: log(1-x)^4.at n=7A052753
- Expansion of e.g.f.: exp(x^2/(1-x)).at n=7A052845
- Triangle arising from solution to a*x = tan x (next row contains non-integral entries).at n=13A059368
- Coefficient triangle of generalized Laguerre polynomials n!*L(n,2,x) (rising powers of x).at n=32A062139
- Fifth column sequence of triangle A062139 (generalized a=2 Laguerre).at n=3A062194
- Index values for new maxima in sequence A007365.at n=23A065932
- Numbers k such that sigma(k+1) = 5*phi(k).at n=4A067263
- Numbers n such that sigma(n)^2 > 9*sigma_2(n) where sigma_2(n) is the sum of squares over the divisors of n.at n=6A068378
- First differences of A069475, successive differences of (n+1)^6-n^6.at n=22A069476
- Number of permutations p of {1,2,3,...,n} such that Sum_{k=1..n} abs(k-p(k)) = 2n.at n=9A072949