12565
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 17280
- Proper Divisor Sum (Aliquot Sum)
- 4715
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8592
- Möbius Function
- -1
- Radical
- 12565
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 125
- 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) = a(n-1) + a(n-7), with a(i) = 1 for i = 0..6.at n=45A005709
- Numbers k such that k, k+1, k+2 and k+3 have the same number of divisors.at n=11A006601
- Numbers k such that sigma(k+2) = sigma(k).at n=21A007373
- Expansion of e.g.f.: tanh(log(1+x))*exp(x).at n=10A009778
- Expansion of 1/(1 - x^7 - x^8 - ...).at n=52A017901
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (natural numbers), t = A000201 (lower Wythoff sequence).at n=43A024863
- a(n) = floor(47*(n-3/2)^(3/2)).at n=41A050256
- Numbers k such that A065608(k) = A065608(k+2).at n=11A065064
- a(n) is the first of a triple of consecutive integers, each of which is the product of three distinct primes.at n=25A066509
- Numbers k such that sigma(k) = phi(k*bigomega(k)+1).at n=43A067876
- Number of distinct products of subsets of integers in the interval [n^2+1, (n+1)^2-1] which are twice a square.at n=51A099500
- G.f. satisfies: A(x) = 1/(1 + x*A(x^7)) and also the continued fraction: 1 + x*A(x^8) = [1; 1/x, 1/x^7, 1/x^49, 1/x^343, ..., 1/x^(7^(n-1)), ...].at n=46A101917
- Numbers n such that 6*p(n)-1 and 6*p(n)+1 are twin primes and 6*p(n+1)-1 and 6*p(n+1)+1 are also twin primes with p(n) = n-th prime.at n=20A126655
- Number of ON states after n generations of cellular automaton based on f.c.c. lattice with each cell adjacent to its twelve neighbors.at n=24A151776
- Products of 3 distinct safe primes.at n=31A157354
- a(n) = n*(21*n-17)/2.at n=35A226491
- Numbers k such that k and k+2 have the same number (A000005) and sum of divisors (A000203).at n=8A229254
- Floor(AGM(n^2, n^3)), where AGM denotes the arithmetic-geometric mean.at n=34A234362
- Triangle T(n, k) = Numbers of non-equivalent (mod D_3) ways to place k points on a triangular grid of side n so that no two of them are adjacent. Triangle read by rows.at n=36A239572
- Number of non-equivalent (mod D_3) ways to place 5 indistinguishable points on a triangular grid of side n so that no two of them are adjacent.at n=5A239575