1617
domain: N
Properties
Digital Properties
- Digit Count
- 4
- Digit Sum
- 15
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 12
- Divisor Sum
- 2736
- Proper Divisor Sum (Aliquot Sum)
- 1119
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Highly Composite
- no
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 840
- Möbius Function
- 0
- Radical
- 231
- Omega Function (Ω)
- 4
- 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
- yes
- 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
- 47
- Smith Number
- no
- Vampire Number
- no
Primality
- Prime
- no
- Composite Number
- yes
- Semiprime
- no
- Squarefree Number
- no
- 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
- Pentagonal numbers: a(n) = n*(3*n-1)/2.at n=33A000326
- Expansion of g.f. (1 + x + 2*x^2)/((1 - x)^2*(1 - x^3)).at n=48A000969
- a(n) is the solution to the postage stamp problem with 6 denominations and n stamps.at n=8A001211
- a(n) = n concatenated with n + 1.at n=15A001704
- Number of nonequivalent dissections of an n-gon into 3 polygons by nonintersecting diagonals rooted at a cell up to rotation and reflection.at n=20A003452
- a(n) = solution to the postage stamp problem with n denominations and 9 stamps.at n=5A005344
- Rook polynomials.at n=6A005777
- Numbers n such that n! has a square number of digits.at n=31A006488
- Coordination sequence T3 for Zeolite Code MFS.at n=25A008175
- Coordination sequence T1 for Zeolite Code NAT.at n=27A008203
- Coordination sequence T1 for Coesite.at n=21A008267
- Coordination sequence T2 for Zeolite Code RSN.at n=26A009886
- a(n) = floor( n*(n-1)*(n-2)*(n-3)/27 ).at n=16A011937
- Odd pentagonal numbers.at n=16A014632
- a(n) is the sum over all floor(k^3/n), k=0 to n inclusive.at n=17A014818
- Numbers n such that phi(n) * sigma(n) + 16 is a perfect square.at n=35A015729
- a(n) = a(n-1) + a(n-2) + 1, with a(0) = 1 and a(1) = 9.at n=12A022323
- a(n) = F(n+2) + c(n) where F(k) is k-th Fibonacci number and c(n) is n-th number that is 1 or is a non-Fibonacci number.at n=14A022800
- a(n) = b(n) + d(n), where b(n) = (n-th Fibonacci number > 2) and d(n) = (n-th non-Fibonacci number).at n=13A023486
- a(n) = b(n) + d(n), where b(n) = (n-th Fibonacci number > 2) and d(n) = (n-th non-Lucas number).at n=13A023494