Properties of the Number 221

Two Hundred Twenty-One

Basics

Value: 220 → 221 → 222

Parity: odd

Prime: No

Previous Prime: 211

Next Prime: 223

Digit Sum: 5

Digital Root: 5

Palindrome: No

Factorization: 13 × 17

Divisors: 1, 13, 17, 221

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 11011101

Octal: 335

Duodecimal: 165

Hexadecimal: dd

Square: 48841

Square Root: 14.866068747318506

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 planar net 3.3.3.3.6 (also called the fsz net). A250120

Numbers in base 3. A7089

Centered square numbers: a(n) = 2·n*(n+1)+1. Sums of two consecutive squares. Also, consider all Pythagorean triples (X, Y, Z=Y+1) ordered by increasing Z; then sequence gives Z values. A1844

Numbers in base 5. A7091

Numbers in base 4. A7090

a(n) = 4·n + 1. A16813

"INVERT" transform of squares A000290. A33453

Integers written in factorial base. A7623

n written in primorial base. A49345

Products of 2 successive primes. A6094

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