16664
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 31260
- Proper Divisor Sum (Aliquot Sum)
- 14596
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8328
- Möbius Function
- 0
- Radical
- 4166
- Omega Function (Ω)
- 4
- 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
- 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
- a(n) = Sum_{k=0..5} binomial(n,k).at n=19A006261
- Number of types of Boolean functions of n variables under a certain group.at n=3A028406
- Super-4 Numbers (4 * n^4 contains substring '4444' in its decimal expansion).at n=11A032744
- Number of partitions of n into parts not of the form 23k, 23k+9 or 23k-9. Also number of partitions with at most 8 parts of size 1 and differences between parts at distance 10 are greater than 1.at n=36A035997
- All differences C(j)-C(i), j>i, of Catalan numbers A000108.at n=40A047075
- Beastly (or hateful) numbers: numbers containing the string 666 in their decimal expansion.at n=29A051003
- Number of 1-punctured staircase polygons (by perimeter) with a hole of perimeter 4.at n=13A055022
- Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=1, r=5, I={0,2,3}.at n=39A079955
- a(n) = Sum_{k=0..floor(n/5)} C(n-4k,k+1).at n=33A099559
- a(n) = A131766(n) / 18.at n=23A131871
- Total number of positive integers below 10^n with 4 positive squares in their representation as sum of squares.at n=4A167615
- Let p = first digit of n, q = number obtained if p is removed from n; let r = last digit of n, s = number obtained if r is removed from n; sequence give n such that p*q = r*s != 0, p! = q, and r! = s.at n=30A245364
- Numbers N such that N = P//Q = R//S, where // is the concatenation function, satisfying the following properties: P and S are m-digit integers, Q and R are k-digit integers, k and m are distinct positive integers, and P*Q = R*S.at n=30A245385
- Numbers in A245385 where P, Q, R, and S are all distinct.at n=11A245386
- Numbers n such that the Phi_n(2) is the product of exactly two primes and is divisible by 2n+1.at n=27A250203
- Positive integers m such that pi(k^3) + pi(m^3) is a cube for some k = 1,...,m, where pi(x) denotes the number of primes not exceeding x.at n=20A262698
- Expansion of Product_{k>=1} (1 - x^(18*k)) * (1 - x^(18*k-9)) * (1 + x^k) / (1 - x^k).at n=23A280947
- Denominators of successive rational approximations converging to 2*Pi from above for n >= 1, with a(-1) = -1 and a(0) = 0.at n=8A299923
- Integers without 0 as a digit, with an odd number of digits, that are not repdigits, and such that the 2 products [d_1 d_2...dk]*[d_k+1 d_k+2...d_2k+1] and [d_1 d_2...d_k+1]*[d_k+2 d_k+2...d_2k+1] are equal.at n=4A385145
- a(n) = Sum_{k=0..n} binomial(4*n-1,k).at n=5A387037