491

Number
$491$ (four hundred and ninety-one) is:


 * The $94$th prime number


 * The smaller of the $7$th pair of primes whose prime gap is $8$:
 * $499 - 491 = 8$


 * The $25$th Sophie Germain prime after $2$, $3$, $5$, $11$, $23$, $29$, $41$, $53$, $83$, $89$, $113$, $131$, $173$, $179$, $191$, $233$, $239$, $251$, $281$, $293$, $359$, $419$, $431$, $443$:
 * $2 \times 491 + 1 = 983$, which is prime.


 * The $34$th long period prime after $7$, $17$, $19$, $23$, $29$, $\ldots$, $269$, $313$, $337$, $367$, $379$, $383$, $389$, $419$, $433$, $461$, $487$

Also see