What is a Prime Number?
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, 7, 11, and 13.
Why Do We Care?
Prime numbers are the "building blocks" of arithmetic. Every integer is either prime itself or can be written as a unique product of primes (The Fundamental Theorem of Arithmetic). They are also crucial for modern cryptography.