16680
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 32
- Divisor Sum
- 50400
- Proper Divisor Sum (Aliquot Sum)
- 33720
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4416
- Möbius Function
- 0
- Radical
- 4170
- 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
- 128
- 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
- Cluster series for honeycomb.at n=18A003204
- Expansion of e.g.f. tan(x)*exp(tan(x)).at n=8A009737
- Expansion of e.g.f. tan(x)*sinh(tan(x)), even powers only.at n=4A009746
- Numbers k such that 2^k - 3 is prime.at n=38A050414
- Numbers k such that sigma(k^2 + 1) == 0 (mod k).at n=33A067719
- Total number of distinct cycles in a particular cellular automata of size n.at n=18A083843
- a(n) equals sum of first n terms of A(x)^n for n>=1, with a(0)=1.at n=6A088358
- Triangle, read by rows, where e.g.f. A(x,y) satisfies: A(x,y) = exp(x*y*A(x,y+1)) and A(x,y) = Sum_{n>=0} Sum_{k>=0} T(n,k)/n!*x^n*y^k.at n=18A096542
- Array read by antidiagonals: T(m,n) = Sum_{i=1..m} i*(n-1+i)!.at n=23A100630
- Table read by antidiagonals: T(m,n) gives the ordinal number in the table of permutations of length n+1 of the permutation which reverses the first m+1 items on a list of length n+1, leaving the remaining items unaltered. For example, T(5,7) is 28494 and the 28494th row of the permutation table of order 8 is 5 4 3 2 1 0 6 7.at n=37A100711
- Number of squarefree words of length n in a 6-ary alphabet.at n=5A214940
- T(n,k) = Number of squarefree words of length n in a (k+1)-ary alphabet.at n=50A214943
- Number of squarefree words of length 6 in an (n+1)-ary alphabet.at n=4A214945
- Number of (n+1)X(n+1) 0..1 arrays with no 2X2 subblock having the sum of its diagonal elements greater than the maximum of its antidiagonal elements.at n=9A251121
- Number of compositions of n such that the maximal distance between two identical parts equals two.at n=22A262194
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 382", based on the 5-celled von Neumann neighborhood.at n=33A271541
- Expansion of Product_{k>=1} ((1-x^(5*k))/(1-x^k))^k.at n=17A285263
- Coefficients in the expansion of Product_{m>=1} (1 - q^(13*m))/(1 - q^m).at n=36A341714
- Numbers k such that A348215(k) = k.at n=27A348216
- Numbers whose binary indices are all semiprimes.at n=38A371454