Properties of the Number 18221

Eighteen Thousand Two Hundred Twenty-One

Basics

Value: 18220 → 18221 → 18222

Parity: odd

Prime: No

Previous Prime: 18217

Next Prime: 18223

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 7 × 19 × 137

Divisors: 1, 7, 19, 133, 137, 959, 2603, 18221

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100011100101101

Octal: 43455

Duodecimal: A665

Hexadecimal: 472d

Square: 332004841

Square Root: 134.98518437221176

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

a(n) = (4·n+1)*(4·n+5). A3185

a(n) = A061037(7·n+2). A165943

Squarefree n such that the elliptic curve n·y² = x³ - x arising in the "congruent number" problem has rank 3. A62693

Expansion of (1 - x + x²)/(1 - x - x⁴). A103632

Number of (19,14)-reverse multiples with n digits. A226517

Losing initial positions in game: two players alternate in removing >= 1 stones; last player wins; first player may not remove all stones; each move <= 3 times previous move. A3411

Group the triangular numbers so that the n-th group sum is a multiple of n. 1, (3, 6, 10, 15), (21), (28), (36, 45, 55, 66, 78), (91, 105, 120, 136, 153, 171, 190), ... Sequence contains n-th group sum divided by n. A114032

Composite squarefree numbers n such that p(i)-3 divides n+3, where p(i) are the prime factors of n. A225703

Row sums of A291940. A291942

a(n) = (6·n+1)*(6·n+5). A1513