The IMEI number or in other words International Mobile Equipment Identity is a unique 15-digit code that precisely identifies the device with the SIM card input. The first 14 digits are defined by GSM Association organization. The last digit is generated by an algorithm named Luhn formula and it has a control character. This number is an individual number assigned to each and every phone all over the world. The easiest way to IMEI check on any phone is to use the *#06# sequence. The IMEI was created because the SIM card number cannot be a permanent identifier of the device. The SIM Card is associated with the user and can be easily transferred from the phone to another phone that’s why IMEI was developed. Why would you need to check the IMEI Number? The number is useful when you would like to send the device for service to fill out warranty forms. Besides that, if you want to report a stolen or a lost phone at the police or network operator you should use the IMEI Number as well. After that, you can block your phone and it will make the device unusable, regardless of whether the SIM card is changed or removed. What is also really important is that IMEI contains a few secret information about the product but also sometimes allows you to locate the smartphone.