15205
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 13
- Digital Root
- 4
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 18252
- Proper Divisor Sum (Aliquot Sum)
- 3047
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 12160
- Möbius Function
- 1
- Radical
- 15205
- Omega Function (Ω)
- 2
- Little Omega Function (ω)
- 2
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
- 32
- Smith Number
- yes
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- yes
- 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
- Numbers k such that the continued fraction for sqrt(k) has period 92.at n=36A020431
- "DGJ" (bracelet, element, labeled) transform of 2,1,1,1...at n=9A032223
- Fifth diagonal (m=4) of triangle A084938; a(n) = A084938(n+4,n) = (n^4 + 18*n^3 + 131*n^2 + 426*n)/24.at n=20A090386
- Triangular sequence from coefficients of Gould polynomials for the special case: n=a=b; g(x,n)=(x/(x - n^2))*binomial(x - n^2, n).at n=25A137373
- Number of strings of numbers x(i=1..5) in 0..n with sum i*x(i)^2 equal to n*25.at n=38A184444
- Indices of primes in A001590.at n=9A231575
- a(n) = Sum_{k=0..n} binomial(k+n-1,k)*binomial(k+n,2*k).at n=6A262910
- Least positive integer x such that n + x^2 = y^3 + z^5 for some positive integers y and z, or 0 if no such x exists.at n=30A266277
- Number of permutations b of length n that satisfy the Diaconis-Graham inequality I_n(b) + EX_n(b) <= D_n(b) with equality.at n=7A301897
- Numbers k such that k^6*2^k - 1 is a prime.at n=11A367478
- Array read by downward antidiagonals: A(n,k) = Sum_{j=0..k + (k mod 3) + 1} A(n-1,j) with A(0,k) = 1, n >= 0, k >= 0.at n=35A369518