(FORTUNE Magazine) – Is the government using Social Security numbers like bar codes? Are there secret formulas in those nine digits to mark Americans by religion, race, gender, and other personal stuff, like dog/cat person? If people read into the number, what can they decode?

Nothing juicy, we're relieved to report. The first three numbers just show the state in which the card was issued. They sweep from New England, where numbers start with 001, to the 500s out west. Thus, New Yorkers get 050 to 134; Alaskans get 574.

Beyond that, you can learn only a few things about someone from his number. If, for example, someone gives you a number that starts above 728, you can tell that he's a liar--those numbers haven't been assigned yet. And if someone's number has 666 in it, you know he doesn't take the Book of Revelation literally. That's because the Social Security Administration will let people trade in a number containing 666 if they object to it. "We will, upon request, upon having documentation that there is religious conviction involved, reassign them a number," says agency spokesman John Trollinger. But there are limits to the SSA's flexibility: If you complain that the number clusters on your card add up to 6-6-6, or that your card contains 999, which looks devilish upside down, the government will tell you to go to hell. So to speak.

Since states are denoted by three digits, it begs us to ask: Which bears the Mark of the Beast? It appears the devil would have gone down to Georgia, but when the agency handed out numbers to growing states, it gave Louisiana 659-665, skipped 666, and then gave Georgia 667-675.

When will we run out of numbers? "Never. Not in our lifetime," Trollinger says. "We have a billion combinations." Since 1936 the SSA has issued 383 million numbers. At the current rate of six million a year, it won't run out until 2101. When that day comes, the SSA hasn't decided whether it'll add a digit or recycle dead people's numbers, but it has plenty of time to figure it out. Assuming, of course, there will still be Social Security in 2101.

--Carol Vinzant