Recently I have changed my mobile number. I did not memorize it yet (learning to keep only indexes to information where it could be found - makes me forget numbers, names etc). So when you quickly try to view your number (for writing in form or giving to a friend) the easiest way is to
Go to home screen
Click on Phone
Navigate to Contacts search top area (taping on top bar) - and there you go
Usually this is done via 2 clicks (2, 3) when you keep your phone on Home screen.