17520
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 40
- Divisor Sum
- 55056
- Proper Divisor Sum (Aliquot Sum)
- 37536
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4608
- Möbius Function
- 0
- Radical
- 2190
- Omega Function (Ω)
- 7
- 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
- yes
- Harshad Number
- yes
- Narcissistic Number
- no
- Collatz Steps
- 79
- 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
- Expansion of Eisenstein series E_4(q) (alternate convention E_2(q)); theta series of E_8 lattice.at n=4A004009
- Theta series of A*_8 lattice.at n=36A023920
- Theta series of tensor cube of A_2 lattice (dimension 8, det 3^12).at n=36A033688
- Expansion of F_9(q^2).at n=72A072839
- Number of full spectrum rook's walks on a (2 X n) board.at n=4A096121
- Numbers k such that 2*10^k + R_k + 6 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=4A102949
- Number of permutations of length n which avoid the patterns 231, 1423, 3214.at n=16A116717
- Triangle read by rows: T(n,k) is the number of permutations of {1,2,...,n} whose 2nd cycle has k entries; each cycle is written with the smallest element first and cycles are arranged in increasing order of their first elements (n>=1; 0<=k<=n-1). For example, 1432=(1)(24)(3) has 2 entries in the 2nd cycle; 3421=(1324) has 0 entries in the 2nd cycle.at n=42A138771
- Number of white corners in all permutations of {1,2,...,n} (for definition see the Eriksson-Linusson references).at n=6A140712
- Determinant of the n X n matrix whose element (r,c) is n for r = c, is -n for c>r, and 1 for c< r.at n=4A177191
- Numbers that are 4-digit palindromes in at least 2 bases.at n=22A180453
- Triangle of coefficients of polynomials u(n,x) jointly generated with A209142; see the Formula section.at n=48A209141
- Triangle of coefficients of polynomials u(n,x) jointly generated with A209746; see the Formula section.at n=51A209745
- Smallest palindromic numbers of length 4 in two bases differing by n.at n=3A216843
- E.g.f. equals the series reversion of tanh(x) / exp(x).at n=5A227466
- Array read by antidiagonals: T(n,m) is the number of (directed) Hamiltonian paths in K_n X K_m.at n=16A269565
- Array read by antidiagonals: T(n,m) is the number of (directed) Hamiltonian paths in K_n X K_m.at n=19A269565
- Number of n X 2 0..5 arrays with some element plus some horizontally or vertically adjacent neighbor totalling five exactly once.at n=2A269761
- Number of n X 3 0..5 arrays with some element plus some horizontally or vertically adjacent neighbor totalling five exactly once.at n=1A269762
- T(n,k)=Number of nXk 0..5 arrays with some element plus some horizontally or vertically adjacent neighbor totalling five exactly once.at n=7A269767