13506
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 27024
- Proper Divisor Sum (Aliquot Sum)
- 13518
- Abundant Number
- yes
- Perfect Number
- no
- Deficient Number
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- yes
Derived Values
- Euler's Totient
- 4500
- Möbius Function
- -1
- Radical
- 13506
- 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
- 76
- Smith Number
- yes
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = Sum_{i=0..n-1} a(i)*a(n-i) with a(0)=1, a(1)=6.at n=7A014435
- a(n) = least m such that if r and s in {1/1, 1/3, 1/5, ..., 1/(2n-1)} satisfy r < s, then r < k/m < (k+4)/m < s for some integer k.at n=38A024847
- Numbers which are the sum of their proper divisors containing the digit 5.at n=15A059464
- a(n) = floor(sqrt(a(n-1)^2 + a(n-2)^2)), a(1)=1, a(2)=3.at n=38A104803
- Smallest number m such that A118164(m) = n.at n=14A118165
- A general recursion triangle with third part a power triangle:m=3; Power triangle: f(n,k,m)=If[n*k*(n - k) == 0, 1, n^m - (k^m + (n - k)^m)]; Recursion: A(n,k,m)=(m*(n - k) + 1)*A(n - 1, k - 1, m) + (m*k + 1)*A(n - 1, k, m) + m*f(n, k, m)*A(n - 2, k - 1, m).at n=22A157630
- A general recursion triangle with third part a power triangle:m=3; Power triangle: f(n,k,m)=If[n*k*(n - k) == 0, 1, n^m - (k^m + (n - k)^m)]; Recursion: A(n,k,m)=(m*(n - k) + 1)*A(n - 1, k - 1, m) + (m*k + 1)*A(n - 1, k, m) + m*f(n, k, m)*A(n - 2, k - 1, m).at n=26A157630
- a(n) is the smallest positive integer that, when written in binary, contains the binary representations of both the n-th prime and the n-th composite as (possibly overlapping) substrings.at n=46A175349
- Numbers starting with 1 such that the sum of any two distinct elements has an even number of distinct prime factors.at n=13A180514
- Number of nondecreasing arrangements of n+2 numbers in 0..8 with the last equal to 8 and each after the second equal to the sum of one or two of the preceding four.at n=23A189325
- Number of (n+1) X 3 0..1 arrays with column and row pair sums b(i,j)=a(i,j)+a(i,j-1) and c(i,j)=a(i,j)+a(i-1,j) such that rows of b(i,j) and columns of c(i,j) are lexicographically nondecreasing.at n=9A203446
- Partitions with parts repeated at most twice and repetition only allowed if first part has an odd index (first index = 1).at n=50A227134
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 289", based on the 5-celled von Neumann neighborhood.at n=27A271127
- G.f. A(x) satisfies: A( x^2*A(x) - x^2*A(x)^2 ) = x^3.at n=10A272463
- Convolution of A048272 and A022567.at n=25A274355
- Centered pentagonal numbers which are products of three distinct primes.at n=10A364610
- Centered pentagonal numbers that are abundant.at n=12A382696
- Cluster series for percolation on the cells of the Cairo tiling.at n=11A390623