Source:

If you have a copy of the Millennium CD then you might be wondering this. What does the numbers mean in Nick's thanks. Well here it is: 5483-5433-86-843-3855378-367-843-388873-47-722723
Live-life-to-the-fullest-for-the-future-is-scarce

To find that out use the phone code.

ABC-2
DEF-3
GHI-4
JKL-5
MNO-6
PQRS-7
TUV-8
WXYZ-9