13718
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 20
- Digital Root
- 2
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 4
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 21720
- Proper Divisor Sum (Aliquot Sum)
- 8002
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6498
- Möbius Function
- 0
- Radical
- 38
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 2
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
- 63
- 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
- yes
- Odd
- no
Appears in sequences
- G.f.: 2*(1-x^3)/((1-x)^5*(1+x)^2).at n=36A005996
- Denominator of sum of -3rd powers of divisors of n.at n=37A017670
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n-k+1), where k = [ n/2 ], s = (1, p(1), p(2), ...), t = (composite numbers).at n=33A025100
- a(n) = 2*n^3.at n=19A033431
- Number of primitive (period n) step cyclic shifted sequence structures using exactly four different symbols.at n=11A056446
- Numbers k such that k | 12^k + 11^k + 1.at n=32A057293
- Numbers n such that n | 8^n + 7^n + 1.at n=8A057297
- a(1) = 1; a(n+1) = (product{k|n} a(k)) (sum{j|n} 1/a(j)), where both the product and sum are over the positive divisors of n.at n=11A068342
- Sum of two powers of 19.at n=9A073214
- Numbers of the form p^3 + q^3, p, q primes.at n=40A086119
- Numbers which are the sum of two positive cubes and divisible by 19.at n=31A102619
- Composite numbers whose exponents in their canonical factorization lie in the geometric progression 1, 3, 9, ...at n=14A102838
- a(n) = 2*(n^2 + 3*n + 1)^3.at n=3A109118
- Cubic polynomial coefficients such that an elliptical term is zero.at n=37A114798
- a(n) = n*floor(n/2)^2.at n=38A122656
- a(n) = ceiling(n/2)*ceiling(n^2/2).at n=38A131474
- a(n) = floor(n/2) * floor(n^2/2).at n=38A131475
- Row sums of triangle A131819.at n=33A131820
- The even composites c such that c=q*g*j*y and q+g=j*y where q,g,j,y are primes.at n=29A167690
- a(n) = 2*prime(n)^3.at n=7A172190