Google Nexus 5 :: Wrong Phone Number In (status) Sub Menu

Got my nice new nexus 5 and its 3 weeks old and I must say its soooo damn good to not have all the stuff put on to other android phones. This phone is simple and uncluttered, love it.

Just one little niggle. When in settings then into "about phone" and then into "status", it shows your phone number. Can some one tell me why its not my phone number. Did not think much of it until I started filling out info on my google stuff and it auto entered some info incuding the phone number, which was of course, wrong.

Simple questions really.
1. where has this number come from.
2. why is it not my number.
3. how do i change it.