In Firefox, when I hover over http://3494943456/ http://3494943456/ it displays as http://208.80.154.224 http://208.80.154.224 in the lower left, as does 1844..

In Firefox, when I hover over http://3494943456/ http://3494943456/ it displays as http://208.80.154.224 http://208.80.154.224 in the lower left, as does 1844... and 197690..., BUT http://7789910752/ http://7789910752/ displays as exactly that string. It likewise navigates to the first, third, and fourth links but breaks on your second.