13185
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
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 22932
- Proper Divisor Sum (Aliquot Sum)
- 9747
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7008
- Möbius Function
- 0
- Radical
- 4395
- 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
- yes
- 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
- no
- Odd
- yes
Appears in sequences
- Number of 3-covers of an unlabeled n-set.at n=16A005783
- a(n) = floor(tau*a(n-2)) + a(n-1) with a(0)=1 and a(1)=3.at n=15A005907
- Number of partitions satisfying (cn(0,5) = 0 and cn(1,5) <= cn(2,5) and cn(1,5) <= cn(3,5) and cn(4,5) <= cn(2,5) and cn(4,5) <= cn(3,5)).at n=51A036812
- Row 3 of array in A047666.at n=26A047667
- Expansion of (1-x)^(-1)/(1-2*x+2*x^3).at n=19A077853
- Number of permutations of length n which avoid the patterns 2314, 4321.at n=8A116708
- Number of (n+2) X 9 0..1 arrays with every 3 X 3 subblock having three equal elements in a row horizontally, vertically or nw-to-se diagonally exactly three ways, and new values 0..1 introduced in row major order.at n=15A204380
- Number of ordered triples (w,x,y) with all terms in {-n,...-1,1,...,n} and w+x+y>0.at n=15A211545
- Number of binary arrays of length n+9 with no more than 5 ones in any length 10 subsequence (=50% duty cycle).at n=5A212399
- Number of binary arrays of length 2*n+5 with no more than n ones in any length 2n subsequence (=50% duty cycle).at n=4A212407
- a(n) = ( 2*n*(2*n^2 + 9*n + 14) + (-1)^n - 1 )/16.at n=36A248851
- Expansion of Sum_{i>=1} i*x^i/(1 - x) * Product_{j=1..i} 1/(1 - x^j).at n=19A284870
- Number of tilings of a 12 X n rectangle using 2*n copies of the disconnected shape [ooo___ooo].at n=24A323423
- Number of ways to write n as an ordered sum of 5 prime powers (including 1).at n=33A341134
- G.f. A(x) satisfies: A(x) = (1 - x * A(-x)) / (1 - 2 * x * A(x)).at n=7A349011
- Odd multiplicative orders of 2+-i modulo primes p == 3 (mod 4).at n=7A385217