13509
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
- 1
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 20800
- Proper Divisor Sum (Aliquot Sum)
- 7291
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8424
- Möbius Function
- 0
- Radical
- 4503
- 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
- 37
- 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
- Number of partitions of 5n such that cn(1,5) = cn(4,5) < cn(0,5) = cn(2,5) = cn(3,5).at n=14A036892
- Number of primes between n^4 and (n+1)^4.at n=36A061235
- a(n) = floor(e^n mod n^e).at n=38A066433
- Number of permutations satisfying -k<=p(i)-i<=r and p(i)-i not in I, i=1..n, with k=1, r=5, I={0,1,4}.at n=41A079956
- Number of permutations of length n which avoid the patterns 2143, 2341, 4312; or avoid the patterns 1234, 1432, 3412.at n=11A116774
- Coefficient of x in the reduction by x^2->x+1 of the polynomial p(n,x) defined below in Comments.at n=17A192760
- Expansion of (1 + 3*x + 4*x^2 - sqrt(1 - 2*x - 7*x^2))/(4 + 8*x).at n=12A212199
- Sum of the prime parts in the partitions of n into 9 parts.at n=32A309470
- Numbers that are the sum of nine fourth powers in nine or more ways.at n=32A345593
- Numbers that are the sum of nine fourth powers in exactly nine ways.at n=27A345851
- a(n) is the Wiener index of a broom on 2n vertices of which n+2 are pendant.at n=24A349416
- Numbers k such that one can make an equilateral triangle from a chain of linked rods of length 1, 2, 3, ..., k, with perimeter equal to the total length.at n=21A382632
- Numbers k such that k - A067666(k) is a square.at n=34A386304
- Numbers k such that sigma(k) = psi(k) + pi(k).at n=6A387999