13853
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
- 2
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 15840
- Proper Divisor Sum (Aliquot Sum)
- 1987
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 11868
- Möbius Function
- 1
- Radical
- 13853
- Omega Function (Ω)
- 2
- 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
- 107
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- a(0) = 1, a(n) = 19*n^2 + 2 for n>0.at n=27A010009
- Discriminants of real quadratic fields with class number 1 and related continued fraction period length of 16.at n=34A050965
- Numbers k such that prime(k+3)-(k+3)*tau(k+3) = prime(k-3)-(k-3)*tau(k-3) where tau(k) = A000005(k) is the number of divisors of k.at n=31A067355
- Triangle P, read by rows, such that P^2 transforms column k of P into column k+1 of P, so that column k of P equals column 0 of P^(2*k+1), where P^2 denotes the matrix square of P.at n=31A113340
- Column 3 of triangle A113340, also equals column 0 of A113340^7.at n=4A113343
- Triangle, read by rows, given by the product Q^2*P^-1, where the triangular matrices involved are P = A113340 and Q = A113350.at n=23A113369
- Number of n X 2 0..3 arrays with no element equal to one plus the sum of elements to its left or zero plus the sum of elements above it or zero plus the sum of the elements diagonally to its northwest or zero plus the sum of the elements antidiagonally to its northeast, modulo 4.at n=27A240756
- a(n) = A066048(a(n-1) + a(n-2)) with a(0) = 0 and a(1) = 1.at n=23A277110
- Number of Dyck paths of semilength n such that the number of peaks in each level is a Fibonacci number.at n=10A288388
- a(n) = Sum_{k=1..n} k * floor(n/k)^3.at n=20A350108
- Number of integer partitions of 2n without a nonempty initial consecutive subsequence summing to n.at n=18A362051
- Number of integer partitions of n without a nonempty initial consecutive subsequence summing to n/2.at n=36A362558