Monday 15 July 2013

What is a prime number?

A prime number is a number which can't be divided exactly by anything but itself and 1. It must be a whole number (an integer) and greater than zero (positive).

For example, 2, 3, 5, and 7 are all prime. But 4 is not, because it can be divided by 2.

Any whole, positive number which is not prime is called a composite number. So, 4 is a composite number.

1 is not a prime number.

Prime numbers go on for ever. There is no limit to how many there are. If you kept counting for ever, you would keep on finding new prime numbers.

1 comment:

  1. Mathematically, any number which has only 1 and the number itself as its factors is called Prime Number. My friend who is an expert in Mathematics also tells me that price numbers are also used in cyber-security at the right place. Prime numbers provide you with uniqueness with no specific pattern between them. Due to this feature, they are extensively used in cyber-security.