Properties of the Number 28640

Twenty-Eight Thousand Six Hundred Forty

Basics

Value: 28639 → 28640 → 28641

Parity: even

Prime: No

Previous Prime: 28631

Next Prime: 28643

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 2 ⁵ × 5 × 179

Divisors: 1, 2, 4, 5, 8, 10, 16, 20, 32, 40

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 110111111100000

Octal: 67740

Duodecimal: 146A8

Hexadecimal: 6fe0

Square: 820249600

Square Root: 169.23356641044944

Classification

Fibonacci: No

Bell Number: No

Factorial Number: No

Regular Number: No

Perfect Number: No

Special

Kaprekar Constant: No

Munchausen Constant: No

Armstrong Number: No

Kaprekar Number: No

Catalan Number: No

Vampire Number: No

Taxicab Number: No

Super Prime: No

Friedman Number: No

Fermat Number: No

Cullen Number: No

OEIS Sequences

Number of unlabeled planar trees (also called plane trees) with n nodes. A2995

Dowling numbers: e.g.f.: exp(x + (exp(b·x) - 1)/b) with b=2. A7405

Number of lattice paths from (0,0) to (n,n) using steps S={(k,0),(0,k),(r,r)|k>0,0<r<=2} which never go above the line y=x. A175939

Expansion of sum ( qⁿ / product( 1-q^k, k=1..6·n), n=0..inf ). A35298

a(n) = φ(A291789(n)). A291805

Triangle A(r,c) read by rows, which contains the row sums of the triangle T(n,k)= T(n-1,k-1)+((c-1)*k+1)*T(n-1,k) in column c. A111579

Number of (w,x,y) with all terms in {0,...,n} and w ≠ min(|w-x|, |x-y|). A213499

Partial sums of A267326. A264390

Square array A(n,k), n >= 0, k >= 1, read by antidiagonals: A(n,k) = exp(-1/k) * ∑_j>=0 (k·j + 1)ⁿ / (k^j * j!). A334165

Array T(n,k) read by antidiagonals: the k-th column contains the first column of the k-th power of A039755. A111670