All the mobiles have a number in-built.
It is written in it by manufacturer and it is a 16digit number this number is usefull when our mobile gets stolen.
We can block the mobile handset by using this number.
With the help of Service provider we can also recover the mobile
just press *#06# you will get a IMEI number. It works for all kinds of mobile.
Just store that number some where it is usefull if your mobile gets lost or stolen.