Properties of the Number 491

Four Hundred Ninety-One

Basics

Value: 490 → 491 → 492

Parity: odd

Prime: Yes

Previous Prime: 487

Next Prime: 499

Digit Sum: 14

Digital Root: 5

Palindrome: No

Factorization: 491

Divisors: 1, 491

Polygonal

Triangular: No

Square: No

Pentagonal: No

Hexagonal: No

Heptagonal: No

Tetrahedral: No

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Representations

Binary: 111101011

Octal: 753

Duodecimal: 34B

Hexadecimal: 1eb

Square: 241081

Square Root: 22.15851980616034

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

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

Primes of the form 4·k + 3. A2145

a(n) = ∑_k=1..n k·floor(n/k); also ∑_k=1..n σ(k) where σ(n) = sum of divisors of n (A000203). A24916

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 with primitive root 2. A1122

Primes of the form 3n-1. A3627

Primes of the form 6k-1. A7528

Number of fractions in Farey series of order n. A5728

Single (or isolated or non-twin) primes: Primes p such that neither p-2 nor p+2 is prime. A7510