Prime number theory is a branch of mathematics that focuses on the properties and distribution of prime numbers. A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. Examples include 2, 3, 5, and 7. Understanding prime numbers is essential because they serve as the building blocks for all natural numbers through multiplication. One of the key areas of study in prime number theory is the Prime Number Theorem, which describes the asymptotic distribution of prime numbers among the integers. This theorem helps mathematicians estimate how many prime numbers exist up to a given number, revealing patterns in their occurrence.