15998
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 32
- Digital Root
- 5
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 25320
- Proper Divisor Sum (Aliquot Sum)
- 9322
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 7560
- Möbius Function
- -1
- Radical
- 15998
- 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
- 190
- 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
- Numbers k such that 255*2^k+1 is prime.at n=38A032504
- a(n) = prime(n)^2 - prime(n+1).at n=30A062235
- Expansion of 2*x^2*(-2+9*x+3*x^2)/((2*x^2+5*x-1)*(2*x^2-5*x+1)).at n=6A106835
- A functionally symmetric Polynomial as a triangle of coefficients: p(x,n)=If[n == 0, 1, (x + 1)^n + 2^(n - 2)*Sum[(3^(m-1) + 2*m-1 )*x^m*(1 + x^(n - 2*m)), {m, 1, n - 1}]].at n=49A146957
- A functionally symmetric Polynomial as a triangle of coefficients: p(x,n)=If[n == 0, 1, (x + 1)^n + 2^(n - 2)*Sum[(3^(m-1) + 2*m-1 )*x^m*(1 + x^(n - 2*m)), {m, 1, n - 1}]].at n=50A146957
- Molecular topological indices of the sunlet graphs.at n=18A192846
- Number of n X 2 0..4 arrays with each element x equal to the number its horizontal and vertical neighbors equal to 2,0,3,4,1 for x=0,1,2,3,4.at n=19A196204
- Number of 0..3 arrays of length n with each element differing from at least one neighbor by 2 or more, starting with 0.at n=10A221510
- Polycyclic aromatic hydrocarbons (for precise definition see He and He, 1986).at n=9A323929
- a(n) is the largest m such that there exists N such that none of S(N), S(N+1), ..., S(N+m-1) is divisible by n, where S(N) is the sum of digits of N.at n=34A331786
- The number of oriented star-like and star trees with n arcs.at n=7A334827
- Expansion of the o.g.f. (2*x^2 + 3*x + 2)*x/((x + 1)^2*(x - 1)^4).at n=37A342397
- Expansion of 1/sqrt((1 - x^3 - x^5)^2 - 4*x^8).at n=35A376784