I just installed the MagicJack iPhone app and called my cellphone to test it out. 239 205 4843 is the number that showed on caller ID.
When I called the number back the app on the iPhone rang. Since I am not pranking anyone it must be from a pool of numbers MagicJack uses for people installing the app. Either I get a reused number from the pool or they assign one each call I'm not sure.
Bottom line since the whole thing seems pretty much anonymous you can get prank calls from anyone with a smartphone from pretty much anywhere in the world.
This caller called twice at 12:15AM. The first call the caller said "Your gonna die in 7 days" the second one my son picked up andsaid we would put harassement charges on them and they didint call back again.