13618
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
- 8
- Divisor Sum
- 22320
- Proper Divisor Sum (Aliquot Sum)
- 8702
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6180
- Möbius Function
- -1
- Radical
- 13618
- Omega Function (Ω)
- 3
- 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
- 182
- 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
- yes
- Odd
- no
Appears in sequences
- a(n) = 10000*log_10(n) rounded up.at n=22A004230
- Number of partitions of n into parts not of the form 17k, 17k+2 or 17k-2. Also number of partitions with 1 part of size 1 and differences between parts at distance 7 are greater than 1.at n=41A035963
- a(0) = 1; for n >= 1, a(n) = Sum_{j=0..a(n-1) mod n} a(j).at n=53A057176
- Maximum sum of products of successive pairs in a permutation of order n+1.at n=33A101986
- Sequence d_n arising in enumeration of arrays of directed blocks (see Quaintance reference for precise definition).at n=9A129880
- Number of 1-separable partitions of n; see Comments.at n=45A239467
- a(n) = (binomial(2n, n) - 2) mod n^3.at n=39A246133
- Numbers k such that A084937(3k) > A084937(3k+1).at n=35A249689
- Number of compositions (ordered partitions) of n into hexagonal pyramidal numbers (A002412).at n=45A322854