Ipad 2 3g 'phone number'

[Gunneruseipad2]

hi how do i find out the 'phone number'* for my 3g ipad 2? I 'm with t-mobile and i want to. remove content lock while
browsing via 3g

* tmobile defines this as the 11 digit number you used to register fior my t-mobile starting with 07

thanks