59,649,589,127,497,217

Number
$59 \, 649 \, 589 \, 127 \, 497 \, 217$ is:


 * The $n$th prime, where $n$ remains to be determined


 * One of the two prime factors of the $7$th Fermat number $2^{\left({2^7}\right)} + 1$, the other being $5 \, 704 \, 689 \, 200 \, 685 \, 129 \, 054 \, 721$:
 * $59 \, 649 \, 589 \, 127 \, 497 \, 217 = 116 \, 503 \, 103 \, 764 \, 643 \times 2^9 + 1$