What is a Prime Number?

A prime number is a natural number greater than 1 that cannot be formed by multiplying two smaller natural numbers. In other words, a prime number is only divisible by 1 and itself.

Examples:

• 2 is the smallest prime number
• 3, 5, 7, 11, 13, 17, 19, 23, 29, 31... are all prime numbers
• 4 is not a prime number because it's divisible by 2 (4 = 2 × 2)

Interesting Facts:

• There are infinitely many prime numbers
• Every even integer greater than 2 can be expressed as the sum of two primes (Goldbach's Conjecture)
• Prime numbers are used in cryptography to secure internet communications