1279

Number

$1279$ (one thousand, two hundred and seventy-nine) is:

The index of the $15$th Mersenne prime after $2$, $3$, $5$, $7$, $13$, $17$, $19$, $31$, $61$, $89$, $107$, $127$, $521$, $607$:

$M_{1279} = 2^{1279} - 1 \approx 1 \cdotp 041 \times 10^{385}$

The $26$th of $29$ primes of the form $2 x^2 + 29$:

$2 \times 25^2 + 29 = 1279$ (Previous ... Next)

The larger of the $43$rd pair of twin primes:

$1279 - 1277 = 2$