[quote:12i7x0ge]It is not possible to get the phone number of the device. Apple doesn't allow this, and it would be bad for users if app developers were easily able to get this somehow, for privacy reasons. The best way to deal with this is ask the user for it if you really want it.
There used to be ways to get the device phone number, but they were basically loopholes, or bugs in iOS, which allowed this. Apple has since fixed these, and it's very obvious that if any new methods were discovered, Apple would be fixing those as well. So it's best to just go the only route that will forever be allowed, which, again, is to ask the user.