12105
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 21060
- Proper Divisor Sum (Aliquot Sum)
- 8955
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6432
- Möbius Function
- 0
- Radical
- 4035
- Omega Function (Ω)
- 4
- 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
- yes
- 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
- 187
- 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
- Cycle class sequence c(2n) (the number of true cycles of length 2n in which a certain node is included) for zeolite PAR = Partheite Ca8[Al16Si16O60(OH)8].16H2O starting with a T3 atom.at n=6A019048
- Numbers k such that the least term in the periodic part of the continued fraction for sqrt(k) is 44.at n=4A031722
- Base 6 digits are, in order, the first n terms of the periodic sequence with initial period 1,3,2,0.at n=5A037711
- Number of partitions satisfying cn(0,5) < cn(1,5) + cn(4,5) + cn(2,5) + cn(3,5).at n=33A039848
- Triangle read by rows: d(n,k) = number of decreasing labeled trees with n nodes and largest leaf <= k, for 1 <= k <= n.at n=31A079268
- Floor( phi * (3/2)^n ) where phi = (1+sqrt(5))/2.at n=22A081226
- Numbers k such that 2*R_k + 7 is prime, where R_k = 11...1 is the repunit (A002275) of length k.at n=12A099410
- Numbers whose anti-divisors sum to a perfect cube.at n=21A109351
- Pentagonal numbers for which the product of the digits is also a pentagonal number.at n=42A117710
- Pentagonal numbers divisible by 5.at n=36A117793
- Triangle read by rows: T(n,k) (n >= 1, 1 <= k <= n) = smallest permanent of any n X n (0,1) matrix with k 1's in each row and column.at n=59A133643
- Pentagonal numbers that are the sum of a nonzero pentagonal number and a nonzero square in at least one way.at n=33A134938
- Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1100-1100-0111 pattern in any orientation.at n=15A146694
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 0, -1), (0, -1, 0), (0, 1, 1), (1, 0, -1)}.at n=9A148773
- a(n) = 25*n^2 + 5.at n=21A158445
- 1/6 the number of n X 2 0..5 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.at n=4A185535
- 1/6 the number of nX5 0..5 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.at n=1A185538
- T(n,k)=1/6 the number of nXk 0..5 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.at n=16A185540
- T(n,k)=1/6 the number of nXk 0..5 arrays with every element equal to exactly one or two of its horizontal and vertical neighbors.at n=19A185540
- Friedman numbers n such that n+1 is also a Friedman number.at n=20A195420