2791

Number
$2791$ (two thousand, seven hundred and ninety-one) is:


 * The $406$th prime number


 * The $31$st centered hexagonal number after $1, 7, 19, 37, 61, 91, 127, \ldots, 1387, 1519, 1657, 1801, 1951, 2107, 2269, 2437, 2611$:
 * $2791 = \displaystyle 1 + \sum_{k \mathop = 1}^{31 - 1} 6 k = 31^3 - 30^3$