How do I retrieve my number password to do the new download?

Connect to your computer and perform the update there. You need to use the computer that you normally use to backup and/or sync your iPhone. If you use a different computer, you will need to authorize it through your own iTunes Apple ID and you will lose all the data currently on your iPhone.

Twokfarm wrote:

Want to do the new update but don't know the four digit number.

There is no four digit number to do updates.

There may be a passcode on the device, but this is the same passcode that the user utilizes on a daily basis to unlock their phone. If you do not know the passcode, is it really your device?