12505
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 15624
- Proper Divisor Sum (Aliquot Sum)
- 3119
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9600
- Möbius Function
- -1
- Radical
- 12505
- 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
- 156
- 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
- Euler numbers written backwards.at n=10A004150
- a(n) = ceiling(n*phi^13), where phi is the golden ratio, A001622.at n=24A004968
- Pseudoprimes to base 14.at n=34A020142
- Strong pseudoprimes to base 32.at n=22A020258
- Vampire numbers: (definition 1): n has a nontrivial factorization using n's digits.at n=28A020342
- a(n) = n*(4*n^4 + 1).at n=5A069078
- Rounded total surface area of a regular icosahedron with edge length n.at n=38A071398
- a(n) = size of union of 2^k (mod 10^n), 0 < k <= 5^n.at n=5A113022
- 5 times pentagonal numbers: 5*n*(3*n-1)/2.at n=41A152734
- a(n) = 338*n - 1.at n=36A157999
- a(n) = 74*n^2 - 1.at n=12A158744
- Number of Goldbach partitions of 6^n.at n=7A180007
- G.f.: A(x) = exp( Sum_{n>=1} 5*5^A112765(n) * x^n/n ), where A112765 is the exponent of the highest power of 5 dividing n.at n=16A195760
- a(n) = 1 + (n-1) + (n-2)*[(n-3)/2] + (n-3)*[(n-4)/2]*[(n-5)/3] + (n-4)*[(n-5)/2]*[(n-6)/3]*[(n-7)/4] +... where [x] = floor(x), with summation extending over the initial [n/2+1] products only.at n=22A207644
- Composite numbers n such that lambda(n) divides 5n-5, where lambda is the Carmichael lambda function (A002322).at n=35A231572
- Numbers m such that there are precisely 7 groups of order m.at n=44A249550
- Decimal representation of the diagonal from the corner to the origin of the n-th stage of growth of the two-dimensional cellular automaton defined by "Rule 966", based on the 5-celled von Neumann neighborhood.at n=43A290832
- Number of 3D walks of type aad.at n=9A302180
- Number of fully normal integer partitions of n.at n=49A317491
- a(n) = Sum_{k=1..n} n^(n/gcd(n, k)).at n=4A332620