Internationumber is an app that lets you convert your numbers that are stored without a country code into a universal number that just works from anywhere in the world. No more problems knowing what number to put in the beginning, nor how many digits you have to add or keep - Internationumber keeps track of everything, and lets you live your life in awesomeness.
It's pretty much as easy as A, B and C:
> You pick a country to convert contacts to
> You select contacts from the list of "unfixed" contacts
> You're done!
If you for some reason end up converting a contact to the wrong country, then all you need to do is restore the backup from inside the app. It can't get any easier than that!
Your contacts will never be used in any malicious fashion, and Internationumber will never transfer your contacts off your device. All backups are stored locally on your device, so don't uninstall the app if you intend on restoring a backup!
Information regarding the permissions:
Read & Write Contacts - needed for the actual changing
Billing - used for in-app billing purposes (donation)