Properties of the Number 421

Four Hundred Twenty-One

Basics

Value: 420 → 421 → 422

Parity: odd

Prime: Yes

Previous Prime: 419

Next Prime: 431

Digit Sum: 7

Digital Root: 7

Palindrome: No

Factorization: 421

Divisors: 1, 421

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 110100101

Octal: 645

Duodecimal: 2B1

Hexadecimal: 1a5

Square: 177241

Square Root: 20.518284528683193

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

Primes of the form x² + xy + 2y², with·and y nonnegative. A106856

Pythagorean primes: primes of the form 4·k + 1. A2144

Greater of twin primes. A6512

Central polygonal numbers: a(n) = n² - n + 1. A2061

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

Primes of the form 6m + 1. A2476

Twin primes. A1097

n written in primorial base. A49345

Primes with primitive root 2. A1122

Primes congruent to 1 or 2 modulo 4; or, primes of form x² + y²; or, -1 is a square mod p. A2313