There are few real-life uses for prime numbers. Nevertheless, they do have a useful purpose in some cases. For instance:
- Circada's only come out at time periods of 13 or 17. These are prime, and mean that a predator coming out at another value (say 4 or 6) will be less likely to catch them.
- Prime numbers are used to contact aliens. They are a simple but universal phenomenon that will indicate our intelligence.
- Prime numbers are used in encryption. It is much harder to crack a code with a big number that is the product of two large prime numbers than one which has lots of factors.
