Create a 7 digit number from an autonumber

Create a 7 digit number from an autonumber

Hello all.

I am wanting to create a serial number that is required to meet a set format. That is:

XXX (preset prefix number)
YYYYYYY (serial number)
Z (check digit)

End result looks like: XXXYYYYYYYZ

I need to use a formula to return the autonumber of the record as a 7 digit number: ie: 1 -> 0000001

Can anyone help with the format for this? 

Regards, Matt.