683

Number
$683$ (six hundred and eighty-three) is:


 * The $124$th prime number


 * The smaller of the $8$th pair of primes whose prime gap is $8$:
 * $691 - 683 = 8$


 * The $31$st Sophie Germain prime after $2$, $3$, $5$, $11$, $23$, $29$, $41$, $\ldots$, $233$, $239$, $251$, $281$, $293$, $359$, $419$, $431$, $443$, $491$, $509$, $593$, $641$, $653$, $659$:
 * $2 \times 683 + 1 = 1367$, which is prime.