13195
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 19
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 3
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 20160
- Proper Divisor Sum (Aliquot Sum)
- 6965
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 8064
- Möbius Function
- 1
- Radical
- 13195
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- 244
- 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
- Expansion of Product_{k>=1} (1-x^k)^29.at n=4A010834
- a(n) = (n-3)*A006918(n-2)/2 for n >= 2, with a(0) = a(1) = 0.at n=29A038376
- Base 8 palindromes that start with 3.at n=32A043023
- a(n) in base 12 is a repdigit.at n=40A048336
- Composite numbers k with no prime factor among (2, 3) (cf. A038509) and such that phi(k) < 2*k/3.at n=38A069043
- Expansion of 1/(1-2x-3x^4).at n=12A099526
- a(n) = n*(n+1)*(n^2-2*n+2)/2.at n=13A101375
- Absolute value of coefficient of term [x^(n-6)] in characteristic polynomial of maximum matrix A of size n X n, where n >= 6. Maximum matrix A(i,j) is MAX(i,j), where indices i and j run from 1 to n.at n=4A112462
- T(n,k) = 4*A046802(n,k) - 2*A008518(n,k) - A007318(n,k), triangle read by rows (0 <= k <= n).at n=31A168291
- T(n,k) = 4*A046802(n,k) - 2*A008518(n,k) - A007318(n,k), triangle read by rows (0 <= k <= n).at n=32A168291
- Number of 1..3 integer arrays v[1..n] of length n with all autocorrelation values sum(i){v[i]*v[i-k]} distinct for k in 0..n-1.at n=8A171277
- Number of 1..n integer arrays v[1..9] of length 9 with all autocorrelation values sum(i){v[i]*v[i-k]} distinct for k in 0..8.at n=2A171346
- Triangle T(n,m), [x*A(x)]^m=sum(n>=m T(n,m)*x^n), where A(x) satisfies x*A(x)^2= -(2*x*A(x)+sqrt(1-4*x*A(x))-1)/(4*x*A(x)+sqrt(1-4*x*A(x))-1).at n=15A188109
- Coefficient of x in the reduction by (x^2 -> x + 1) of the polynomial p(n,x) given in Comments.at n=9A192875
- G.f. satisfies: A(x) = Sum_{n>=0} x^n * Sum_{k=0..n} x^k * {[x^k] A(x)^(3*n)}.at n=9A249936
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 654", based on the 5-celled von Neumann neighborhood.at n=34A273332
- G.f. A(x) satisfies: A(x) = 1/(1 - 2*x*A(x) - x*A(x)/(1 - x*A(x)/(1 - x*A(x)/(1 - ...)))), a continued fraction.at n=5A307489
- a(n) = (1/24)*n*(n - 1)*(n - 3)*(n - 14).at n=29A319930
- Dirichlet convolution of the integer partition numbers A000041 with the strict partition numbers A000009.at n=34A323765
- Products k of 4 distinct primes (or tetraprimes) such that k has no squarefree neighbors.at n=10A364141