556

Number
$556$ (five hundred and fifty-six) is:
 * $2^2 \times 139$


 * The $45$th untouchable number after $2, 5, 52, 88, 96, 120, 124, \ldots, 406, 408, 426, 430, 448, 472, 474, 498, 516, 518, 520, 530, 540, 552$.