12756
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 29792
- Proper Divisor Sum (Aliquot Sum)
- 17036
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 4248
- Möbius Function
- 0
- Radical
- 6378
- 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
- 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
- 125
- 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
- McKay-Thompson series of class 6E for Monster (and, apart from signs, of class 12B).at n=38A007258
- Expansion of 1/(1-x^4-x^5-x^6-x^7-x^8-x^9-x^10).at n=37A017832
- Number of 2's in all partitions of n.at n=30A024786
- A variant of the recurrence for A001190.at n=17A038750
- McKay-Thompson series of class 6E for the Monster group with a(0) = 1.at n=38A045488
- Let (u1,u2) be successive untouchable numbers such that phi(u1) = phi(u2); sequence gives values of u1.at n=28A048189
- Numbers k such that 291*2^k + 1 is prime.at n=29A053362
- Number of positive numbers m such that A073642(m) = n.at n=55A087135
- McKay-Thompson series of class 6E for the Monster group with a(0) = 3.at n=38A105559
- McKay-Thompson series of class 12B for the Monster group.at n=38A112148
- Number of (directed) Hamiltonian paths on the 4 X n knight graph.at n=6A123935
- McKay-Thompson series of class 6E for the Monster group with a(0) = -5.at n=38A128632
- McKay-Thompson series of class 6E for the Monster group with a(0) = 4.at n=38A128633
- Expansion of phi(-q^5) / phi(-q) in powers of q where phi() is a Ramanujan theta function.at n=24A138526
- Number of permutations of 1..n with all differences of elements separated by distances 1 or 2 being respectively unique.at n=9A170808
- McKay-Thompson series of class 12B for the Monster group with a(0) = 5.at n=38A187146
- McKay-Thompson series of class 12B for the Monster group with a(0) = -4.at n=38A187147
- McKay-Thompson series of class 12B for the Monster group with a(0) = -3.at n=38A187148
- a(0)=1; thereafter a(n) = n! + Sum_{i=0..n-1} a(i)*a(n-1-i).at n=7A229741
- a(n) is a refactorable number and the sum of all refactorable numbers <= a(n) is also a refactorable number.at n=26A235177