In taped sit-down, the pair share a laugh over 9-9-9 and Cain jokes Letterman is “trying real hard” to convince him not to run for president.

Letterman: “9-9-9. It’s fun… And you ought to get some sort of toll free number. Herman Cain, you dial 9-9-9, you get a free pizza!”

Cain: “You know what you’re going to get? Instead of a free pizza when you dial 9-9-9, you’re gonna be able to get a job.”