Number check code is a serial code that can be used to check your own phone number. See an explanation of this number here.

The IMSI number of the SIM is a series of identification numbers that you must know. see more information about the number here.

IMSI Catcher Detector is a multifunctional tool that can help you in various ways.

There are lots of GSM IMSI Catcher Software that you can download to catch IMSI numbers around you. See further explanation here.