2047

Number
$2047$ (two thousand and forty-seven) is:


 * $23 \times 89$


 * The $5$th Mersenne number after $3, 7, 31, 127$:
 * $2047 = 2^{11} - 1$


 * The $8$th Poulet number after $341, 561, 645, 1105, 1387, 1729, 1905$:
 * $2^{2047} \equiv 2 \pmod {2047}$: $2047 = 23 \times 89$