The IMEI (International Mobile Equipment Identity) number is a 15 digit serial number unique to each and every phone.
You'll usually find it printed on the back of your phone or on the SIM tray.
Alternatively you can have your mobile display
its IMEI number by typing the following on the keypad:
If your handset displays more than 15 digits or is separated by symbols, please enter the first 15 digits only.