Properties of the Number 18780

Eighteen Thousand Seven Hundred Eighty

Basics

Value: 18779 → 18780 → 18781

Parity: even

Prime: No

Previous Prime: 18773

Next Prime: 18787

Digit Sum: 24

Digital Root: 6

Palindrome: No

Factorization: 2 ² × 3 × 5 × 313

Divisors: 1, 2, 3, 4, 5, 6, 10, 12, 15, 20

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100100101011100

Octal: 44534

Duodecimal: AA50

Hexadecimal: 495c

Square: 352688400

Square Root: 137.0401401050072

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

Expansion of g.f. 1/ (1-x¹*(1-x^m+1)/ (1-x²*(1-x^m+2)/ (1- ... ))) for m=9. A228645

Sums of 4 distinct powers of 5. A38476

a(n) = usigma(A276086(n)), where usigma (A034448) is multiplicative with a(p^e) = (p^e)+1, and A276086 gives the prime product form of primorial base expansion of n. A348996

G.f.: exp( ∑_n>=1 (σ(2·n) - σ(n))*Lucas(n)*xⁿ/n ), where Lucas(n) = A000204(n) and σ(n) = A000203(n) is the sum of divisors of n. A225524

Triangle read by rows: T(n,k) is the number of weighted lattice paths in L_n having k (1,1)-steps. L_n is the set of lattice paths of weight n that start at (0,0) and end on the horizontal axis and whose steps are of the following four kinds: a (1,0)-step with weight 1; a (1,0)-step with weight 2; a (1,1)-step with weight 2; a (1,-1)-step with weight 1. The weight of a path is the sum of the weights of its steps. A182880

Triangle read by rows: coefficients of polynomials Q_n(x) arising in study of Riemann ζ function. A217940

Number of nX4 0..2 arrays with no element equal to zero plus the sum of elements to its left or zero plus the sum of elements above it or zero plus the sum of the elements diagonally to its northwest, modulo 3. A240035

Partial sums of the number of active (ON, black) cells in n-th stage of growth of two-dimensional cellular automaton defined by "Rule 259", based on the 5-celled von Neumann neighborhood. A271056

Irregular triangle read by rows: T(n, k) is the number of n-step closed walks on the hexagonal lattice having algebraic area k. A353091

Number of nonempty subsets of {1,2,...,n} in which exactly 3/4 of the elements are <= n/3. A47197