15591
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
- 3
Divisibility
- Divisor Count
- 4
- Divisor Sum
- 20792
- Proper Divisor Sum (Aliquot Sum)
- 5201
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10392
- Möbius Function
- 1
- Radical
- 15591
- 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
- yes
- Harshad Number
- no
- Narcissistic Number
- no
- Collatz Steps
- 84
- Smith Number
- no
- 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
- Number of partitions of at most n into at most 5 parts.at n=39A002622
- Radii of the circles around (0,0) that contain record numbers of lattice points, rounded up to the next integer.at n=20A071384
- Number of positions that are exactly n moves from the starting position in the Rashkey Type 2 puzzle.at n=9A079857
- Sum of pyramid weights of all dispersed Dyck paths of length n (i.e., of all Motzkin paths of length n with no (1,0) steps at positive heights).at n=14A191319
- Number of partitions p = [x(1), ..., x(k)], where x(1) >= x(2) >= ... >= x(k), of n such that max(x(i) - x(i-1)) is a part of p.at n=41A241735
- a(n) = Sum_{k=0..n} k*binomial(2*k,k)/2.at n=7A277178
- Number of orderless same-trees of weight n with all leaves equal to 1.at n=47A289079
- Expansion of 1/(2 - Product_{k>=2} 1/(1 - x^k)).at n=18A307057
- Number of finite sets of set partitions of {1,...,n} such that any two have meet {{1},...,{n}} and join {{1,...,n}}.at n=5A318532
- A(n, k) = [x^k] (1 - 4*x)^(-n/2)*x/(1 - x), square array read by ascending antidiagonals with n >= 0 and k >= 0.at n=62A323222
- Number of integer compositions of n with all prime run-lengths.at n=29A353401
- a(n) is the smallest k such that k!'s prime(n)-smooth part is less than its prime(n+1)-rough part.at n=29A360316