12815
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 17
- Digital Root
- 8
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 16848
- Proper Divisor Sum (Aliquot Sum)
- 4033
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9280
- Möbius Function
- -1
- Radical
- 12815
- 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
- 169
- 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
- Iccanobif numbers: reverse digits of two previous terms and add.at n=14A001129
- a(n) = 7*a(n-1) - a(n-2) + 4, with a(0) = 0, a(1) = 5.at n=5A003482
- a(n) = [ a(n-1)/a(1) ] + [ a(n-2)/a(2) ] + ... + [ a(1)/a(n-1) ], for n >= 3.at n=30A022870
- Expansion of Molien series for 16-D extraspecial group 2^{1+2*4}.at n=5A030535
- Denominators of continued fraction convergents to sqrt(347).at n=11A041657
- Number of polyominoes with n cells, symmetric about diagonal 2.at n=35A056878
- a(n) = F(n)*F(n-1) if n odd otherwise F(n)*F(n-1)-1, where F = Fibonacci numbers A000045.at n=11A059840
- Sum of numbers in n-th upward diagonal of triangle in A079826.at n=43A079825
- a(n) = F(3)*F(n)*F(n+1) + F(4)*F(n+1)^2 - F(4) if n even, F(3)*F(n)*F(n+1) + F(4)*F(n+1)^2 if n odd, where F(n) is the n-th Fibonacci number (A000045).at n=9A080143
- Number of divisor chains of length n which begin with n ("anchored" divisor chains).at n=30A094097
- Number of divisor chains of length 2n+1 which are both cyclic and anchored.at n=15A094099
- Positive values of k such that there is exactly one permutation p of (1,2,3,...,k) such that i+p(i) is a Fibonacci number for 1<=i<=k.at n=19A097083
- Triangle Q, read by rows, such that Q^3 transforms column k of Q^2 into column k+1 of Q^2, so that column k of Q^2 equals column 0 of Q^(3*k+2), where Q^3 denotes the matrix cube of Q.at n=16A113381
- Column 1 of triangle A113381, also equals column 0 of A113370^5.at n=4A113382
- Triangle, read by rows, given by the product R^3*Q^-2 using triangular matrices Q=A113381, R=A113389.at n=10A114154
- Triangle, read by rows, given by the product Q^-2*P^3 using triangular matrices P=A113370, Q=A113381.at n=23A114155
- Number of permutations of length n which avoid the patterns 2341, 3214, 4123.at n=9A116795
- Numerator of Sum_{k=1..n} 1/(Fibonacci(k)*Fibonacci(k+2)).at n=9A119996
- Number of partitions of n containing a clique of size 7.at n=41A183564
- Inverse of Riordan array ((1-x)(1-x^2)(1-x^3)/(1-x^6), x(1-x)(1-x^2)(1-x^3)/(1-x^6)).at n=59A185967