Who called from 3139891634

This just keep calking my phone and don't say nothing who could this be

This # keeps calling and then hangs up when u answer.  when u call back it says the subscriber cannot be reached! what the heck and who is it?!

This # keeps calling and then hangs up when u answer.  when u call back it says the subscriber cannot be reached! what the heck and who is it?!