How can i get the phone number out of the phone

[Bigd0720]

This IMEI number 356518070191409 belongs to who

 

[Saga Lout]

Assuming you've found it, call your own phone, note the number then ring someone in their Contacts to ask for a message to be passed on to ring you. If you look in the Logs, you might find the person they rang most often.