Properties of the Number 281

Two Hundred Eighty-One

Basics

Value: 280 → 281 → 282

Parity: odd

Prime: Yes

Previous Prime: 277

Next Prime: 283

Digit Sum: 11

Digital Root: 2

Palindrome: No

Factorization: 281

Divisors: 1, 281

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 100011001

Octal: 431

Duodecimal: 1B5

Hexadecimal: 119

Square: 78961

Square Root: 16.76305461424021

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

Lesser of twin primes. A1359

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

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

Sum of the first n primes. A7504

Sophie Germain primes p: 2p+1 is also prime. A5384

Twin primes. A1097

Primes of the form 2x² + 2xy + 17y². A139827

Ramanujan primes R_n: a(n) is the smallest number such that if x >= a(n), then π(x) - π(x/2) >= n, where π(x) is the number of primes <= x. A104272

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

Primes of the form 3n-1. A3627

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