Properties of the Number 21675

Twenty-One Thousand Six Hundred Seventy-Five

Basics

Value: 21674 → 21675 → 21676

Parity: odd

Prime: No

Previous Prime: 21673

Next Prime: 21683

Digit Sum: 21

Digital Root: 3

Palindrome: No

Factorization: 3 × 5 ² × 17 ²

Divisors: 1, 3, 5, 15, 17, 25, 51, 75, 85, 255

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 101010010101011

Octal: 52253

Duodecimal: 10663

Hexadecimal: 54ab

Square: 469805625

Square Root: 147.22431864335456

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 (2,4,8) tiling of hyperbolic plane. A265063

Numbers n that are the hypotenuse of exactly 12 distinct integer-sided right triangles, i.e., n² can be written as a sum of two squares in 12 ways. A97226

Positions of 3's in A264977; positions of 6's in A277330. A277713

Numbers that are the sum of three squares in arithmetic progression. A292313

Number of n X n matrices over GF(4) with rank 1. A60869

G.f.: 1 + ∑_n>=1 a(n)*xⁿ/(1 - xⁿ) = ∏_n>=1 (1 + xⁿ)ⁿ. A300276

Odd numbers k such that A166100((k-1)/2)/k is not an integer. A166102

3·h², where h is an odd integer not divisible by 3. A229852

Number of compositions (ordered partitions) of n into octagonal pyramidal numbers (A002414). A322856

Array read by ascending antidiagonals: A(n, k) = (kⁿ - 1)²/(k - 1), with k >= 2. A379587