What’s so great about prime numbers?

That was my question after a Federal Express employee made headlines in January for discovering the largest known prime—a whopper with 23 million digits.

Not to dis Jonathan Pace, the Tennessean who made the discovery, but what can you do with a number that, if spelled out, would consume 77 reams of paper and, by one estimate, take nearly four years to read aloud?

The answer is not much. At least not yet.

But times change.