16809
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 24
- Digital Root
- 6
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 1
Divisibility
- Divisor Count
- 8
- Divisor Sum
- 24192
- Proper Divisor Sum (Aliquot Sum)
- 7383
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 10320
- Möbius Function
- -1
- Radical
- 16809
- 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
- 159
- 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
- no
- Odd
- yes
Appears in sequences
- a(n) = s(1)t(n) + s(2)t(n-1) + ... + s(k)t(n+1-k), where k = [ (n+1)/2 ], s = (composite numbers), t = (odd natural numbers).at n=36A024590
- Numbers k such that the continued fraction for sqrt(k) has even period and if the last term of the periodic part is deleted the central term is 86.at n=34A031584
- Numbers whose base-7 representation contains exactly four 0's.at n=7A043396
- a(n) = 10*n^2 - 1.at n=40A158447
- Half the number of (n+1)X2 binary arrays with equal numbers of majority one 2X2 subblocks and majority zero 2X2 subblocks.at n=7A184459
- Half the number of (n+1)X9 binary arrays with equal numbers of majority one 2X2 subblocks and majority zero 2X2 subblocks.at n=0A184466
- T(n,k)=Half the number of (n+1)X(k+1) binary arrays with equal numbers of majority one 2X2 subblocks and majority zero 2X2 subblocks.at n=28A184467
- T(n,k)=Half the number of (n+1)X(k+1) binary arrays with equal numbers of majority one 2X2 subblocks and majority zero 2X2 subblocks.at n=35A184467
- G.f.: A(x) = 1 + x*F(x)*G(x) where F(x) = A(x/F(x)) and G(x) = A(x*G(x)).at n=8A184509
- Minimal number (in decimal representation) with n nonprime substrings in base-7 representation (substrings with leading zeros are considered to be nonprime).at n=19A217107
- Number of (n+1) X (3+1) 0..1 arrays with nondecreasing x(i,j)-x(i,j-1) in the i direction and nondecreasing x(i,j)-x(i-1,j) in the j direction.at n=8A250606
- Coordination sequence for (2,3,7) tiling of hyperbolic plane.at n=48A265057
- Number of distinct fountains of n coins.at n=21A288006
- a(n) = Sum_{d|n} min(d, n/d)^5.at n=48A297795
- Number of nX4 0..1 arrays with every element unequal to 2, 3, 4, 5, 6, 7 or 8 king-move adjacent elements, with upper left element zero.at n=4A317461
- Number of nX5 0..1 arrays with every element unequal to 2, 3, 4, 5, 6, 7 or 8 king-move adjacent elements, with upper left element zero.at n=3A317462
- T(n,k)=Number of nXk 0..1 arrays with every element unequal to 2, 3, 4, 5, 6, 7 or 8 king-move adjacent elements, with upper left element zero.at n=31A317465
- T(n,k)=Number of nXk 0..1 arrays with every element unequal to 2, 3, 4, 5, 6, 7 or 8 king-move adjacent elements, with upper left element zero.at n=32A317465
- Number of nontrivial equivalence classes of S_n under the {1234,3412} pattern-replacement equivalence.at n=41A330395
- a(n) is the number of regions formed by n-secting the angles of an octagon.at n=34A335769