12726
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
- 24
- Divisor Sum
- 31824
- Proper Divisor Sum (Aliquot Sum)
- 19098
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 3600
- Möbius Function
- 0
- Radical
- 4242
- Omega Function (Ω)
- 5
- Little Omega Function (ω)
- 4
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
- yes
- 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
- yes
- Odd
- no
Appears in sequences
- Number of inequivalent planar partitions of n, when considering them as 3D objects.at n=20A000786
- Ruth-Aaron numbers (1): sum of prime divisors of n = sum of prime divisors of n+1.at n=19A006145
- a(n) = T(n,[ n/2 ]), where T is the array in A026323.at n=13A026336
- a(n) is the numerator of the n-th convergent of [L_1, L_2, L_3, ...] where L_i is the period of the continued fraction for sqrt(i).at n=13A053190
- a(n) is the numerator of the n-th convergent of [L_1, L_2, L_3, ...] where L_i is the period of the continued fraction for sqrt(i).at n=15A053190
- Numbers k such that sopf(k) = sopfr(k+1), where sopf(k) = A008472(k) and sopfr(k) = A001414(k).at n=23A064678
- Numbers k such that iterating phi(sigma(k)-phi(k)) starting from k leads to the fixed point 8064.at n=22A077096
- Signed array used for numerators of generating functions of the column sequences of array A090452.at n=55A091029
- A triangular array made from polynomial coefficients of A049614.at n=47A118687
- Triangle where T(n,k) = n!/(n-k)!*[x^k] ( x/(2*x + log(1-x)) )^(n+1), for n>=k>=0, read by rows.at n=39A118788
- The sequence c[n] defined in A126939.at n=9A126942
- Numbers n that raised to the powers from 1 to k (with k>=1) are multiple of the sum of their digits (n raised to k+1 must not be a multiple). Case k=8.at n=21A135193
- G.f. satisfies: A(x) = B(x/A(x)) where A(x) = Sum_{n>=0} a(n)*x^n/[n!*(n+1)!/2^n] and B(x) = A(x*B(x)) = Sum_{n>=0} x^n/[n!*(n+1)!/2^n].at n=5A155927
- Number of n-step self-avoiding walks on square lattice plus number of n-step self-avoiding walks on hexagonal [ =triangular ] lattice.at n=6A177238
- The number of partitions of the set [n] where each element can be colored 1 or 2 avoiding the patterns 1^11^2 and 1^22^1 in the pattern sense.at n=7A209797
- Number of (n+2)X(1+2) 0..3 arrays with no row, column, diagonal or antidiagonal in any 3X3 subblock summing to 3 or 6.at n=0A252322
- T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with no row, column, diagonal or antidiagonal in any 3X3 subblock summing to 3 or 6.at n=0A252325
- Irregular triangle read by rows: T(n,k) is the number of dominating subsets with cardinality k of the n X n rook graph (n >= 0, 0 <= k <= n^2).at n=26A368831
- Smaller term of each Ruth-Aaron pair in which the sum of distinct prime factors is a prime number.at n=5A372455
- a(n) is the total sum of semiperimeters over all (>=,>=)-polyominoes of length n.at n=9A382988