A prime number is a natural number greater than 1 that has no positive divisors other than 1 and itself. In other words, a prime number is a number that cannot be formed by multiplying two smaller natural numbers.
- Uniqueness: Each prime number is unique and cannot be divided by any other numbers except for 1 and itself.
- Infinitude: There are infinitely many prime numbers. This was proven by the ancient Greek mathematician Euclid around 300 BCE.
- Prime Factorization: Every integer greater than 1 is either a prime number or can be factored into prime numbers, which are unique to that number (Fundamental Theorem of Arithmetic).
Here are some examples of prime numbers:
- 2 (the only even prime number)
- 3
- 5
- 7
- 11
- 13
- 17
- 19
- 23
- 29
To determine if a number ( n ) is prime:
- Check if ( n ) is less than 2. If so, it's not a prime number.
- Check if ( n ) is exactly 2. If so, it is a prime number.
- For numbers greater than 2, check divisibility from 2 up to the square root of ( n ). If ( n ) is not divisible by any of these numbers, it is prime.