you need to show the number "ready for dialing".
That, of course, means prepending location-specific "9", "1" or "011"(?) code. And ommiting area code for local calls that must have it ommitted.
Or, for some reports, you'd have to show it in the most generic format, as in +(country)-(area)-(phone)
What I am trying to say, you need to support a whole lot of ways to render the phone if you really want to do it right. And storing it as a bunch of digits will probably not work.