13395
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 23040
- Proper Divisor Sum (Aliquot Sum)
- 9645
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6624
- Möbius Function
- 1
- Radical
- 13395
- 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
- 94
- 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
- Number of decimal digits in n-th Mersenne prime.at n=26A028335
- Base 8 palindromes that start with 3.at n=35A043023
- 21-gonal numbers: a(n) = n*(19n - 17)/2.at n=38A051873
- A diagonal of A008296.at n=17A059302
- a(1)=1, a(n+1) = a(n) + spf(Sum_{i=1..n} a(i)), where spf=A020639 (smallest prime factor).at n=24A080180
- Number of partitions p of n for which Odd(p) = Odd(p') (mod 4), where p' is the conjugate of p.at n=39A097566
- a(1) = 1, a(2) = 2; a(n) = lcm(n, a(n-2)), a(n+1) = lcm((n+1), a(n-3)) and so on until a(2n-1) = lcm(2n-1, a(1)). Then a(2n) = lcm(2n, a(2n-2)) and so on.at n=46A109849
- Primitive elements of A119432.at n=27A119433
- Number of digits in n-th even superperfect number A061652(n).at n=26A138883
- Number of walks within N^3 (the first octant of Z^3) starting at (0,0,0) and consisting of n steps taken from {(-1, -1, 0), (-1, 1, -1), (-1, 1, 1), (0, 1, -1), (1, 0, 0)}.at n=10A148244
- x-values in the solution to 17*x^2 + 16 = y^2.at n=7A199774
- Number of nX3 0..1 arrays with every element equal to 1, 2, 4, 5, 6 or 7 king-move adjacent elements, with upper left element zero.at n=9A299309
- Squarefree numbers m such that the equation x*(x+1)*(x+2) = m*y^2 has more than one solution (x,y) with x>0 and y>0.at n=6A335715
- G.f. satisfies A(x) = Sum_{n>=1} A(x^3)^n / A(x^(2*n)), with A(0) = 0 and A'(0) = 1.at n=27A383376