The Emergency Number worldwide for Mobile is 112. If you find yourself out of the coverage area of your mobile; network and there is an emergency, dial 112 and the mobile will search any existing network to establish the emergency number for you, and interestingly this number 112 can be dialed even if the keypad is locked. Try it out.
Imagine your mobile battery is very low. To activate, press the keys *3370# Your mobile will restart with this reserve and the instrument will show a 50% increase in battery. This reserve will get charged when you charge your mobile next time.
To check your Mobile phone's serial number, key in the following digits on your phone * # 0 6 #
THINGS YOU PROBABLY NEVER KNEW YOUR MOBILE PHONE COULD DO 
