15807
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 21
- Digital Root
- 3
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 23040
- Proper Divisor Sum (Aliquot Sum)
- 7233
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 9560
- Möbius Function
- -1
- Radical
- 15807
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 177
- 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
- a(n) = n*(29*n + 1)/2.at n=33A022287
- Number of ways to partition n elements into pie slices of different sizes other than one.at n=39A032155
- Partial sums of A001159: Sum_{j=1..n} sigma_4(j).at n=8A064604
- Numbers n such that phi((prime(n)+1)/2)=sigma(n).at n=34A068473
- Number of 0..n arrays x(0..11) of 12 elements with zero 6th differences.at n=39A200374
- Odd numbers n such that the sum of the binary digits of n and n^2 both equal 12.at n=13A261593
- Largest number of maximum matchings in a tree of n vertices.at n=30A333347
- a(n) = (3n - 9/2 - 1/n + 6/(n+1))*binomial(2n-2,n-1).at n=5A344717
- Number of odd chordless cycles of length >=5 in the n-Goldberg graph.at n=4A362546