The Riemann hypothesis is a mathematical statement about some special numbers called prime numbers. Prime numbers are numbers like 3, 5, 7, 11 and 17 that can only be divided by themselves and 1. The Riemann hypothesis says that the special numbers in mathematics called Riemann zeta are related to the prime numbers in a special way. It's like a puzzle and lots of mathematicians are trying to solve it. If we can prove the Riemann hypothesis it will help us understand the prime numbers better. Understanding primes could have lots of cool applications.