123

Number
$123$ (one hundred and twenty-three) is:


 * $3 \times 41$


 * The $10$th Lucas number after $(2), 1, 3, 4, 7, 11, 18, 29, 47, 76$:
 * $123 = 47 + 76$


 * The index (after $2, 3, 6, 30, 75, 81, 115$) of the $8$th Woodall prime:
 * $123 \times 2^{123} - 1$