8191

Number
$8191$ (eight thousand, one hundred and ninety-one) is:


 * The $1028$th prime number


 * The $6$th Mersenne number after $3, 7, 31, 127, 2047$:
 * $8191 = 2^{13} - 1$


 * The $5$th Mersenne prime after $3, 7, 31, 127$:
 * $8191 = 2^{13} - 1$