16786
domain: N
Properties
Digital Properties
- Digit Count
- 5
- Digit Sum
- 28
- Digital Root
- 1
- Palindromic Number
- no
- Repdigit
- no
- Automorphic
- no
- Kaprekar Number
- no
- Multiplicative Persistence
- 2
Divisibility
- Divisor Count
- 16
- Divisor Sum
- 31680
- Proper Divisor Sum (Aliquot Sum)
- 14894
- Abundant Number
- no
- Perfect Number
- no
- Deficient Number
- yes
- Weird Number
- no
- Untouchable Number
- no
- Primitive Abundant
- no
Derived Values
- Euler's Totient
- 6480
- Möbius Function
- 1
- Radical
- 16786
- Omega Function (Ω)
- 4
- Little Omega Function (ω)
- 4
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
- 128
- 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
- T(n,0) + T(n,1) + ... + T(n,n), T given by A026659.at n=13A026666
- Lattice animals in the cubic diamond lattice (4 nearest neighbors), even-vertex-connected cubes.at n=7A039740
- Eigentriangle by rows, termwise products of A078812 and its eigensequence, A125274.at n=34A144254
- Number of ways to place 2 queens on an n X n chessboard so that they attack each other.at n=21A144945
- Coefficient of x in the reduction by (x^2->x+1) of the polynomial p(n,x) given in Comments.at n=9A192877
- Number of partitions of n whose mean is a part.at n=56A237984
- a(n) = Catalan(n) - n.at n=10A246604
- Number of (n+2)X(2+2) 0..3 arrays with every 3X3 subblock row and column sum not equal to 0 1 3 6 or 7 and every 3X3 diagonal and antidiagonal sum equal to 0 1 3 6 or 7.at n=6A252151
- Number of (n+2)X(7+2) 0..3 arrays with every 3X3 subblock row and column sum not equal to 0 1 3 6 or 7 and every 3X3 diagonal and antidiagonal sum equal to 0 1 3 6 or 7.at n=1A252156
- T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum not equal to 0 1 3 6 or 7 and every 3X3 diagonal and antidiagonal sum equal to 0 1 3 6 or 7.at n=29A252157
- T(n,k)=Number of (n+2)X(k+2) 0..3 arrays with every 3X3 subblock row and column sum not equal to 0 1 3 6 or 7 and every 3X3 diagonal and antidiagonal sum equal to 0 1 3 6 or 7.at n=34A252157
- Numbers n such that n, p=prime(n) and q=prime(p) have the same sum of digits.at n=27A261142
- Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 654", based on the 5-celled von Neumann neighborhood.at n=37A273332
- Expansion of ((sqrt(2)-1)*(-sqrt(2);x)_inf - (sqrt(2)+1)*(sqrt(2);x)_inf)/2, where (a;q)_inf is the q-Pochhammer symbol.at n=52A278296
- A246604 (Catalan(n)-n) with initial terms 1,0,0,2 changed to 1,1,1,3.at n=10A289615
- A246604 (Catalan(n)-n) with initial terms 1,0,0,2,10 changed to 1,1,1,2,11.at n=10A289616
- Number of compositions of n whose Lyndon factorization is uniform.at n=17A329397
- Triangle read by rows: T(n,k) is the number of parking functions of length n with k strict descents. T(n,k) for n >= 1 and 0 <= k <= n-1.at n=43A333829
- Numbers that are the sum of an emirp and its reversal in more than one way.at n=24A345408
- Triangle read by rows: T(n,k) is k-th entry of the toric g-vector of the n-dimensional associahedron, 0 <= k <= floor(n/2).at n=26A390883