Properties of the Number 21188

Twenty-One Thousand One Hundred Eighty-Eight

Basics

Value: 21187 → 21188 → 21189

Parity: even

Prime: No

Previous Prime: 21187

Next Prime: 21191

Digit Sum: 20

Digital Root: 2

Palindrome: No

Factorization: 2 ² × 5297

Divisors: 1, 2, 4, 5297, 10594, 21188

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101001011000100

Octal: 51304

Duodecimal: 10318

Hexadecimal: 52c4

Square: 448931344

Square Root: 145.5609837834301

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

Coordination sequence for (2,4,6) tiling of hyperbolic plane. A265061

Numbers k such that (2·k)!/(2*(k!)²) - 1 is prime. A112861

Numbers k such that k·2^m+1 are composites for all exponents m in the range 0<=m<=k. A61153

Table read by rows: T(n,k) = number of k-sided polygons in an equal-armed cross with arms of length n (see Comments in A331456 for definition) for k = 3,4,5,6,7. A333037

The first Zagreb index of the Aztec diamond AZ(n) (see the Ramanes et al. reference, Theorem 2.1). A292344

Sequence shifts left ten places under Weigh transform with a(n) = signum(n) for n<10. A316082

Consider the figure made up of a row of n adjacent congruent rectangles, with diagonals of all possible rectangles drawn; a(n) is the number of interior vertices where exactly four lines cross. A336490

Triangle read by rows: T(n,k) is the coefficient A_k in the transformation of 1 + x + x² + ... + xⁿ to the polynomial A_k*(x+(-1)^k)^k for 0 <= k <= n. A248975

Solution of the complementary equation a(n) = a(n-1) + a(n-2) + b(n-2)*b(n), where a(0) = 1, a(1) = 3, b(0) = 2, b(1) = 4, b(2) = 5, and (a(n)) and (b(n)) are increasing complementary sequences. A296267

Expansion of e.g.f. exp((1-sqrt(1-4·log(1+x)))/2). A184975