[ipince]

Well, yeah, pretty much.

In number theory you study properties/patterns of the numbers. This is an example of such a property.

These properties often seem like they don’t have any applications, and often they don’t, but not always. For example, cryptography is basically all based on number theory.

[seph-reed]

I watched a great series once on generating ~prime numbers which explained how to use number theory to check a randomly generated number for a probability of being prime. By using a bunch of weird rules, you can be ~99% sure it's prime without having to do huge computations.