The IMEI (International Mobile Equipment Identity) is a unique 15-digit number assigned to every mobile phone and some satellite phones. This identifier distinguishes each device from others on cellular networks. Mobile operators use the IMEI to track devices, block stolen phones from accessing the network, and help recover lost or stolen phones. Unlike SIM cards, which identify the user, the IMEI identifies the hardware itself. Knowing your phone’s IMEI is important for security and in case you need to report your device as lost or stolen.