Did you buy a new mobile, If you bought it through a cellular operator it most probably has a valid IMEI number.But in some countries you can buy a
Mobile Handset over the counter and choose the mobile operator and use the SIM provided, but in this case we cannot be sure if the IMEI number is valid.
The International Mobile Equipment Identity or IMEI is a number unique to every GSM and WCDMA and iDEN mobile phone as well as some satellite phones. It is usually found printed on the phone underneath the battery. It can be found by typing *#06# on a handset. (Source – Wikiepedia)
Incase you mobile phone is stolen,having a valid IMEI number and knowing it can help stop its use on any network by intimating your IMEI code to the mobile phone operator. Image source : Movilae
You can check if the IMEI number of your mobile number is valid or not by visiting NumberingPlans and entering your unique 15 digit IMEI code can help find details about your phone like information regarding manufacturer, model type, and country of approval of a handset.
Check your IMEI @ NumberingPlans