16816
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 22
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 10
- Divisor Sum
- 32612
- Proper Divisor Sum (Aliquot Sum)
- 15796
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8400
- Möbius Function
- 0
- Radical
- 2102
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 2
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
- 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
- Number of semi-regular digraphs (with loops) on n unlabeled nodes with each node having out-degree 2.at n=4A003286
- Discriminants of quintic fields with 2 complex conjugates (negated).at n=26A023684
- Trajectory of 1 under map n->21n+1 if n odd, n->n/2 if n even.at n=13A033967
- Trajectory of 3 under map n->21*n+1 if n odd, n->n/2 if n even.at n=20A037108
- a(1) = 1, a(n)= number obtained by replacing each digit of a(n-1) with four times its value.at n=4A061580
- a(1) = 1, a(n) = number obtained by replacing each digit of a(n-1) with its double.at n=8A061581
- Numbers n such that (2^n+1)^4-2 is prime.at n=9A100496
- Generator for the finite sequence A038178.at n=15A135480
- Number of n X n arrays of squares of integers summing to 20 with every element equal to at least one neighbor.at n=2A146514
- Numbers of the form a^b + c^d where a, b, c and d are the first 4 primes.at n=9A168349
- Numbers of the form 3^j + 7^k, for j and k >= 0.at n=46A226816
- Numbers of the form 7^j + 9^k, for j and k >= 0.at n=26A226831
- Triangle read by rows: T(n,k) is the number of semi-regular relations on n nodes with each node having out-degree k (0 <= k <= n).at n=23A259471
- Triangle read by rows: T(n,k) is the number of semi-regular relations on n nodes with each node having out-degree k (0 <= k <= n).at n=25A259471
- a(n) = Sum_{k=0..n} (-1)^(k+1) * k * A000041(n-k).at n=43A270143
- G.f. A(x) satisfies: A(x - x*A'(x)) = x^2.at n=4A276369
- Expansion of Product_{k=1..9} theta_3(q^k), where theta_3() is the Jacobi theta function.at n=47A320241
- a(n) is the number of vertices formed by n-secting the angles of an octagon.at n=34A335770
- Third Lie-Betti number of a path graph on n vertices.at n=43A361230
- a(n) is the least number that reaches 1 after n iterations of the infinitary totient function A064380.at n=32A362025