17920
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 40
- Divisor Sum
- 49104
- Proper Divisor Sum (Aliquot Sum)
- 31184
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6144
- Möbius Function
- 0
- Radical
- 70
- Omega Function (Ω)
- 11
- 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
- no
- Narcissistic Number
- no
- Collatz Steps
- 22
- 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
- Generalized Fibonacci numbers A_{n,3}.at n=34A006208
- E.g.f.: exp(tan(x)-tanh(x))=1+4/3!*x^3+160/6!*x^6+544/7!*x^7+17920/9!*x^9...at n=9A013451
- Expansion of e.g.f. sin(arctan(x) - arctanh(x)) (odd powers only).at n=4A013463
- Triangle of coefficients in expansion of (1+4x)^n.at n=40A013611
- Triangle of coefficients in expansion of (1+8x)^n.at n=31A013615
- Number of reversible strings with n-1 beads of 2 colors. 4 beads are black. String is not palindromic.at n=27A032091
- Triangle whose (i,j)-th entry is binomial(i,j)*2^i.at n=40A038208
- Triangle whose (i,j)-th entry is binomial(i,j)*4^(i-j).at n=40A038231
- Triangle whose (i,j)-th entry is binomial(i,j)*8^(i-j)*1^j.at n=32A038279
- 5-fold convolution of A000302 (powers of 4); expansion of 1/(1-4*x)^5.at n=4A040075
- Denominators of continued fraction convergents to sqrt(214).at n=11A041399
- a(n) = binomial(n-1,4)*n^(n-5).at n=7A053509
- Number of step shifted (decimated) sequences using a maximum of four different symbols.at n=7A056373
- Scaled Chebyshev U-polynomials evaluated at sqrt(2).at n=5A057084
- Coefficient triangle of polynomials (rising powers) related to Pell number convolutions. Companion triangle is A058403.at n=20A058402
- Coefficient triangle of polynomials (falling powers) related to Pell number convolutions. Companion triangle is A058405.at n=15A058404
- Triangle of idempotent numbers binomial(n,k)*k^(n-k), version 1.at n=40A059297
- Triangle of idempotent numbers binomial(n,k)*k^(n-k), version 2.at n=31A059298
- Triangle of idempotent numbers (version 3), T(n, k) = binomial(n, k) * (n - k)^k.at n=40A059299
- Triangle of idempotent numbers binomial(n,k)*k^(n-k), version 4.at n=32A059300