664,579

Number
$664 \, 579$ (six hundred and sixty-four thousand, five hundred and seventy-nine) is:


 * The $53 \, 911$th prime number


 * The number of primes with no more than $7$ digits:
 * $2$, $3$, $5$, $7$, $11$, $13$, $17$, $19$, $23$, $\ldots$, $9 \, 999 \, 943$, $9 \, 999 \, 971$, $9 \, 999 \, 973$, $9 \, 999 \, 991$