Prime Number

Let us define prime number. A Prime number is a whole number which is divided by number 1 and itself so this is the prime numbers definition. Prime numbers has following properties:-

• They are always positive.
• They are non-zeros numbers.
• They are always greater than 1.
• They always have two factors.

Therefore a prime number can be defined as the whole number greater than 1 which exactly has two divisors that is number 1 and the number itself.

Zero and one are not considered as prime numbers. 2 is the smallest and only even prime number. All other even numbers are divided by 2 so they are not prime numbers.

The prime numbers up to 100 are 2, 3, 5, 7, 11, 13, 17, 19, 23, 29, 31, 37, 41, 43, 47, 53, 59, 61, 67, 71, 73, 79, 83, 89, 97 .The list of prime numbers to 100 is given below:-

The table above shows the list of all prime numbers to 100.The numbers that are multiplied to get a product are called the factors of the product. Prime numbers are numbers which do not have any factors other than 1 and number itself. To find out if the number is a prime number, we start dividing it by 2, if it is divisible then it is not a prime number and if it is not then we continue dividing it by 3, 5, 7, and 11 and so on till we get any factors. If we get any factors then it is a non-prime number or a composite number.

Examples:-

• 2 have factors 1 and 2 so 2 is a prime number.
• 3 have factors 1 and 3 so 3 is a prime number.
• 4 have factors 1, 2 and 4 so it is not a prime number.
• 5 have factors 1 and 5 so it is a prime number.
• 6 have factors 1, 2, 3 and 6 so it is not a prime number.