16687
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 28
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 19152
- Proper Divisor Sum (Aliquot Sum)
- 2465
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 14400
- Möbius Function
- -1
- Radical
- 16687
- Omega Function (Ω)
- 3
- 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
- 115
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- yes
- 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
- no
- Odd
- yes
Appears in sequences
- a(n) = n*a(n-1) + (n-1)*a(n-2), a(0) = 1, a(1) = 1.at n=7A000255
- Triangle giving number L(n,k) of normalized k X n Latin rectangles.at n=37A001009
- a(n) = Fibonacci(n+1) - 2^floor(n/2).at n=21A005672
- Triangle read by rows: T(n,k) is the number of permutations of [n] having k consecutive ascending pairs (0 <= k <= n-1).at n=35A010027
- Irregular triangle read by rows: T(n,k) (n>=1, 0 <= k <= floor(n/2)) = number of permutations of 1..n with exactly floor(n/2) - k runs of consecutive pairs up.at n=23A010029
- Odd heptagonal numbers (A000566).at n=41A014637
- 7th differences of factorial numbers.at n=1A023044
- Triangular array formed from successive differences of factorial numbers.at n=43A047920
- Numerator of Sum_{k=0..n} (-1)^k/k!.at n=9A053557
- Smallest number k such that x/(sum of digits of x) = k has exactly n solutions.at n=18A058913
- Triangular array formed from successive differences of factorial numbers, then with factorials removed.at n=43A060475
- Triangle T[n,m]: T[n,-1] = 0; T[0,0] = 0; T[n,0] = n*n!; T[n,m] = T[n,m-1] - T[n-1,m-1].at n=34A061312
- Positions of non-crossing fixed-point-free involutions encoded by A014486 in A055089. Permutation of A064640.at n=10A064638
- Positions of non-crossing fixed-point-free involutions encoded by A014486 (after reflection) in A055089. Permutation of A064640.at n=14A064639
- Positions of non-crossing fixed-point-free involutions (encoded by A014486) in A055089, sorted to ascending order.at n=14A064640
- Euler's difference table: triangle read by rows, formed by starting with factorial numbers (A000142) and repeatedly taking differences. T(n,n) = n!, T(n,k) = T(n,k+1) - T(n-1,k).at n=37A068106
- Table T(n,k) giving number of ways of obtaining exactly 0 correct answers on an (n,k)-matching problem (1 <= k <= n).at n=34A076731
- Diagonal sums of triangle A008949.at n=19A079284
- First differences of A079284.at n=20A079285
- Subminimal numbers, from minimal numbers by analogy with subfactorials.at n=50A079717