How to cheack phone number (all bd operators )

Here I give you the code,so that you can easily your mobile sim card number.

For Grameenphone users :
 Dial: *2#
For Robi users:
Dial: *140*2*4#

For Banglalink users:
Dial:*511# 

For Airtel users:

Dial: *121*6*3#