This past week, a FedEx employee from Germantown, Tenn., made a massive discovery — and it wasn't in any packages. John Pace found the largest prime number known to humankind.
And that number goes on to more than 23 million digits.
"So it's longer than anybody really wants to sit down and hear," he says.
If you're not great at math, here's a primer: Prime numbers can only be divided by 1 and themselves.