12717
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
- 4
Divisibility
- Divisor Count
- 10
- Divisor Sum
- 19118
- Proper Divisor Sum (Aliquot Sum)
- 6401
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8424
- Möbius Function
- 0
- Radical
- 471
- 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
- 81
- 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
- no
- Odd
- yes
Appears in sequences
- a(n) = prime(n)*(prime(n+1)-1)/2.at n=36A014303
- Composite numbers k such that the sum of the proper divisors of k not including 1, (Chowla's function, A048050) and their product (A007956) are both perfect squares.at n=33A064180
- Number of n-node unlabeled connected oriented graphs whose underlying graphs are mating graphs, cf. A006024.at n=5A102599
- Numbers k such that abundance(k) = abundance(sigma(k)).at n=3A137210
- a(n) = 44*n^2 + 1.at n=17A158630
- a(n) = n^2 + 731*n + 1.at n=17A180919
- Number of n X 2 binary arrays indicating whether each 2 X 2 subblock of a larger binary array has lexicographically increasing rows and columns, for some larger (n+1) X 3 binary array with rows and columns of the latter in lexicographically nondecreasing order.at n=15A227085
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 483", based on the 5-celled von Neumann neighborhood.at n=25A267829
- Triangle read by rows: row n gives coefficients of Schur polynomial Omega(n) in order of decreasing powers of x.at n=73A269750
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 437", based on the 5-celled von Neumann neighborhood.at n=25A272155
- Numbers k such that (14*10^k - 53) / 3 is prime.at n=23A280206
- G.f.: A(x,y) = (1-y) * Sum_{n>=0} y^n * (1 + x*(1-y)^2)^(n^2).at n=68A303920
- G.f.: A(x,y) = (1-y) * Sum_{n>=0} y^n * (1 + x*(1-y)^2)^(n^2).at n=77A303920
- Number of integer partitions of n for which the parts have the same median as the multiplicities.at n=43A360456
- a(n) = Sum_{k=2..n} binomial(k,2) * floor(n/k).at n=39A366967