# Number theory

**Number theory** is a part of mathematics. It explains what some types of numbers are, what properties they have, and ways that they can be useful.

Topics in number theory are:

Important theorems in number theory are:

- Chinese remainder theorem
- Fundamental theorem of arithmetic
- Fermat's last theorem
- Fermat's little theorem

## Applications

A well-known application of number theory is encrypted messaging (encryption). Data compression also makes use of the field.