15818
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 23
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 25920
- Proper Divisor Sum (Aliquot Sum)
- 10102
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7180
- Möbius Function
- -1
- Radical
- 15818
- 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
- 146
- 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
- Number of antichains in rooted plane trees on n nodes.at n=7A007852
- Expansion of tan(log(1+x))/exp(x).at n=7A009648
- Numbers k such that 85*2^k+1 is prime.at n=20A032392
- Limit of reversed rows of triangle A126470, in which row sums equal the factorials.at n=19A126471
- Number of 4-step S, NW and NE-moving king's tours on an n X n board summed over all starting positions.at n=25A187378
- Start with a single cell at coordinates (0, 0, 0), then iteratively subdivide the grid into 3 X 3 X 3 cells and remove the cells whose sum of modulo 2 coordinates is 3; a(n) is the number of cells after n iterations.at n=3A285397
- Composite numbers whose sum of aliquot parts divide the sum of the squares of their aliquot parts.at n=33A301482
- G.f. A(x) satisfies: A(x) = 1 + x + x^2 + x^3 + x^4 + x^5*A(x)^2.at n=30A307972
- Number of solutions to x^2 + y^2 + z^2 + w^2 <= n^2, where x, y, z, w are positive odd integers.at n=30A349611
- Numbers k such that the centered cube number k^3 + (k+1)^3 is equal to at least two other sums of two cubes.at n=9A352221
- Expansion of Sum_{k>0} (1/(1-x^k)^6 - 1).at n=14A363696
- Number of maximal subsets of {1..n} containing n such that it is possible to choose a different binary index of each element.at n=28A370641