17820
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
- 60
- Divisor Sum
- 60984
- Proper Divisor Sum (Aliquot Sum)
- 43164
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4320
- Möbius Function
- 0
- Radical
- 330
- 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
- 97
- 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
- An upper bound on the biplanar crossing number of the complete graph on n nodes.at n=47A007333
- Numbers k such that k and 4*k are anagrams.at n=6A023088
- a(n) = 5*(n+1)*binomial(n+4,5)/2.at n=7A027801
- a(n) = 30*(n+1)*binomial(n+4,10).at n=2A027806
- Dirichlet convolution of b_n=2^(n-1) with Catalan numbers.at n=10A034739
- Dirichlet convolution of Fibonacci numbers with phi(n).at n=21A034748
- 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=24A036458
- Engel expansion of sinh(1/3).at n=22A068380
- Ooguri-Vafa invariants of disk degeneracies for brane III in the O(K) -> P^1 x P^1 geometry.at n=8A092707
- Ooguri-Vafa invariants of disk degeneracies for brane III in the O(K) -> P^1 x P^1 geometry.at n=4A092711
- Integers that are Rhonda numbers to more than one base.at n=35A100988
- Numbers j such that j divides the sum of the digits of j!.at n=21A108825
- t(n)_n where t() = triangular numbers A000217.at n=43A122634
- Number of 5-way intersections in the interior of a regular 6n-gon.at n=44A137939
- a(n) = Catalan(n) + 2^n - 0^n.at n=10A141353
- Bell polynomial B(n,k){3,6,6,0,...,0}.at n=18A187082
- Numbers with prime factorization pqr^2s^4.at n=14A190107
- Numbers k which use half of the ten digits such that they have at least one factorization k=p*q that uses remaining half of the digits that are not in k.at n=4A195814
- Numbers x whose digits can be permuted to produce a multiple of x.at n=34A245680
- Numbers n = p * q, where n, p, and q together contain all 10 digits at least once.at n=4A253172