There's no such concept as an integer with padding. How many legs do you have - 2, 02 or 002? They're the same number. Indeed, even the "2" part isn't really part of the number, it's only relevant in the decimal representation.
If you need padding, that suggests you're talking about the textual representation of a number... i.e. a string.
You can achieve that using string formatting options, e.g.
string text = value.ToString("0000000");
or
string text = value.ToString("D7");