What Does International Mobile Equipment Identity (IMEI) Mean?
International Mobile Equipment Identity (IMEI) is a number that facilitates device validity identification. The IMEI number is unique and typically 15 or 17 digits, which are stored on the battery’s backside. The IMEI is strictly used for identification by by Global System for Mobile Communications (GSM), Wideband Code Division Multiple Access (WCDMA) and some satellite devices.The IMEI number does not have a permanent subscriber relationship. Swapping a Security Information Management (SIM) card cannot prevent phone banning because the IMEI number is stored inside the phone - not the SIM card.
Techopedia Explains International Mobile Equipment Identity (IMEI)
The most common IMEI format is AA-BBBBBB-CCCCCC-D, described as follows: