86,243

Number
$86 \, 243$ (eighty-six thousand, two hundred and forty-three) is:


 * The $8384$th prime number


 * The index of the $28$th Mersenne prime after $2$, $3$, $5$, $7$, $13$, $\ldots$, $2203$, $2281$, $3217$, $4253$, $4423$, $9689$, $9941$, $11 \, 213$, $19 \, 937$, $21 \, 701$, $23 \, 209$, $44 \, 497$:
 * $M_{86 \, 243} = 2^{86 \, 243} - 1 \approx 5 \cdotp 369 \times 10^{25 \, 961}$