What are Prime Numbers?
Prime numbers are positive integers greater than 1 that are divisible only by 1 and themselves. This means they cannot be formed by multiplying two smaller natural numbers. They are the building blocks of all natural numbers, much like atoms are the building blocks of matter. Any whole number greater than 1 is either a prime or can be uniquely factored into primes — a concept known as the Fundamental Theorem of Arithmetic.
Examples of prime numbers:
2, 3, 5, 7, 11, 13, 17, 19, 23, 29...
Note:
- 2 is the only even prime number.
- 1 is not considered a prime number.
A Brief History
Prime numbers have fascinated mathematicians for thousands of years. The ancient Greeks, particularly Euclid around 300 BCE, were among the first to formally study them. In his book Elements, Euclid proved that there are infinitely many prime numbers — a theorem still taught today.
Over time, primes became central in number theory. Mathematicians like Euler, Gauss, and Riemann explored their patterns and distributions. Despite their simple definition, prime numbers appear to be randomly scattered along the number line — a mystery that has led to deep mathematical questions, like the still-unsolved Riemann Hypothesis.
Today, prime numbers are not just of theoretical interest — they are crucial in modern fields like cryptography, especially in securing digital communications and online banking.