Check the number in the phone’s Contacts app
Open the Phone or Dialer app and view the caller ID or recent calls
Go to Settings and look under About Phone or Phone Status
Check the SIM card settings on the device
Review the mobile carrier account or billing statement
Look at saved messages or call logs for the number
Use a contact backup or sync service to find stored numbers
Ask the phone owner directly
Use a reverse phone lookup service
Check the number on the device label, packaging, or account paperwork