13131
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 9
- Digital Root
- 9
- Palindromic Number
- yes
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 6
- Divisor Sum
- 18980
- Proper Divisor Sum (Aliquot Sum)
- 5849
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8748
- Möbius Function
- 0
- Radical
- 4377
- Omega Function (Ω)
- 3
- Little Omega Function (ω)
- 2
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
- yes
- Narcissistic Number
- no
- Collatz Steps
- 76
- 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
- Numbers k such that (k / product of digits of k) is 1 or a prime.at n=37A001103
- Numbers that are the sum of 11 positive 8th powers.at n=23A003389
- Octahedral numbers: a(n) = n*(2*n^2 + 1)/3.at n=27A005900
- Numbers that are palindromic in bases 8 and 10.at n=17A029804
- Palindromic Super-2 Numbers.at n=17A032750
- Numbers having only digits 1 and 3 in their decimal representation.at n=40A032917
- a(n) = a(n-1) + a(round(2*(n-1)/3)) + a(round((n-1)/3)) with a(1)=a(2)=1.at n=36A033499
- Numbers with multiplicative digital root value 9.at n=27A034056
- Decimal expansion of a(n) is given by the first n terms of the periodic sequence with initial period 1,3.at n=4A037582
- Base 8 palindromes that start with 3.at n=31A043023
- Palindromic and divisible by 9.at n=26A045644
- a(n+1) is smallest number with a(n+1)^n > a(n)^(n+1).at n=21A059923
- a(n) = (2*n - 1)*(8*n^2 - 8*n + 3)/3.at n=13A063496
- Nonprimes whose sum of digits is equal to its product of digits.at n=36A066307
- Numbers with at least 2 distinct digits and whose "rotations" (including the number itself) are multiples of these digits; repeated digits allowed but digit 0 not allowed.at n=16A066484
- Number of potential flows in n X n array with integer velocities in -13..13, i.e., number of n X n arrays with adjacent elements differing by no more than 13, counting arrays differing by a constant only once.at n=1A068760
- Palindromes whose product of digits is a positive palindrome.at n=42A082207
- Palindromes divisible by their digit sum.at n=38A082232
- Triangle whose n-th row contains n smallest palindromes with a digit sum of n.at n=44A082264
- n-th largest palindrome whose digit sum is n.at n=8A082265