[vesinisa]

Interestingly, your phone number is actually not stored on the SIM card. It instead holds a globally unique ICCID number which your operator links to your account (phone number) on their systems.

This actually makes it possible to transfer your phone number between SIM cards or even operators, and means your cell phone is blissfully unaware of its own phone number.

[megous]

While interesting, it's irrelevant. Google can take your number the moment you enter your SIM into the phone. They even have it as a feature.

[namibj]

It's surprisingly annoying if the phone is unaware, like mine!