15805
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
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 19800
- Proper Divisor Sum (Aliquot Sum)
- 3995
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12096
- Möbius Function
- -1
- Radical
- 15805
- 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
- 76
- 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 ordered quadruples of integers from [ 2,n ] with no global factor.at n=23A015638
- Pseudoprimes to base 17.at n=35A020145
- Strong pseudoprimes to base 17.at n=12A020243
- a(n) = (3*n+1)*(4*n+1).at n=36A033577
- Numbers whose base-5 representation contains exactly three 0's and three 1's.at n=32A045172
- a(n) = A050314(2n+1,1): column 1 of triangle.at n=24A050316
- a(n) is the first of a triple of consecutive integers, each of which is the product of three distinct primes.at n=37A066509
- a(n) = (n+1)*prime(n) + n*prime(n+1).at n=41A097240
- Expansion of 1/(x^k*(1-x-2*x^(k+1))) for k=6.at n=30A143449
- Positive numbers y such that y^2 is of the form x^2+(x+809)^2 with integer x.at n=6A160203
- Sum of all numbers from 2*n-1 up to prime(n).at n=45A161626
- Partial sums of A028388 good primes (version 2).at n=42A172166
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 1006", based on the 5-celled von Neumann neighborhood.at n=32A273861
- Expansion of Product_{k>=0} (1 + x^(5*k+4))^(5*k+4).at n=45A285340
- Numbers k for which rank of the elliptic curve y^2=x^3-k*x is 4.at n=11A309034
- Number of rooted self-avoiding knight's paths of length n on an infinite chessboard with first move specified.at n=5A323559
- Number of odd-length integer partitions of n with integer alternating product.at n=47A347444
- Number of integer partitions of n with integer reverse-alternating product.at n=47A347445