216,091

Number
$216 \, 091$ (two hundred and sixteen thousand and ninety-one) is:


 * The $19 \, 292$nd prime number


 * The index of the $31$st Mersenne prime after $2$, $3$, $5$, $7$, $13$, $\ldots$, $11 \, 213$, $19 \, 937$, $21 \, 701$, $23 \, 209$, $44 \, 497$, $86 \, 243$, $110 \, 503$, $132 \, 049$:
 * $M_{216 \, 091} = 2^{216 \, 091} - 1 \approx 7 \cdotp 461 \times 10^{65 \, 049}$