13365
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
- 24
- Divisor Sum
- 26208
- Proper Divisor Sum (Aliquot Sum)
- 12843
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6480
- Möbius Function
- 0
- Radical
- 165
- Omega Function (Ω)
- 7
- 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
- 138
- 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
- Numbers k such that phi(k) = phi(k+1).at n=19A001274
- Expansion of 1/((1-10x)(1-11x)(1-12x)).at n=3A021021
- Odd numbers divisible by exactly 7 primes (counted with multiplicity).at n=10A046320
- One of the three sequences associated with the polynomial x^3 - 2.at n=13A052101
- Number of permutations s of {1,2,...,n} such that |s(i)-i|>2 for each i=1,2,...,n.at n=10A075851
- a(n) = S(n,4) where S(n,m) = Sum_{k=0..n} binomial(n,k)*Fibonacci(m*k).at n=5A087426
- Draw a line through every pair of points with coordinates (x, 1) and (x', 2) with x, x' in 1..n, and then count the number of intersection points above the line y = 2.at n=20A092275
- Expansion of g.f. c(3x)^4, where c(x) is the g.f. of A000108.at n=4A101602
- Riordan array (1, x*c(3x)), c(x) the g.f. of A000108.at n=40A110518
- Terms in A112039 that are divisible by 3, divided by 3.at n=22A112040
- Coefficients of Pi^(2*n+1) in a certain integer relation involving Ramanujan exponential-type sums.at n=3A119542
- Product of n^2 and n-th tetrahedral number: a(n) = n^3*(n+1)*(n+2)/6.at n=9A119771
- Numbers n for which nontrivial positive magic squares of exactly 10 different orders with magic sum n exist. For a definition of nontrivial positive magic squares, see A125005.at n=32A125017
- Denominators of Blandin-Diaz compositional Bernoulli numbers C_2,n.at n=10A133005
- Numbers n such that phi(n)=d_1!!*d_2!!*...*d_k!! where d_1 d_2 ... d_k is the decimal expansion of n.at n=12A139408
- Union of A052103, A052102 and A052101, uniqued and sorted.at n=32A140495
- "Trim" numbers that are not prime; see reference for definition.at n=35A145555
- Number of n X n binary arrays symmetric about both diagonal and antidiagonal with all ones connected only in a 1110-0100-0111 pattern in any orientation.at n=16A146875
- 5 times heptagonal numbers: a(n) = 5*n*(5*n-3)/2.at n=33A153785
- Number of ON cells at n-th stage of three-dimensional version of the cellular automaton A160117 using cubes.at n=14A160379