Types Of Numbers

Types of Numbers

Even Numbers:

In the given number the number in its units place is either 0, 2, 4, 6 or 8, and then the number is an even number.

(Or)

If the given number is divisible by 2 then the number is also an even number.

Odd Numbers:

In the given number the number in its units place is either 1, 3, 5, 7, or 9, and then the number is an odd number.

(Or)

If the given number leaves remainder 1 when divided by 2 then the number is also an odd number.

Prime Numbers:

If the given numbers are having the factors 1 and the number itself then the numbers are called prime numbers.

Examples: 2= 1x2, 3=1x3, 5= 1x5, 7= 1x7, 11=1x11, 13=1x13 …etc

The prime numbers are 2,3,5,7,11,13,17,19,23,29,31,37 …etc

Note:  2 is the only even prime number.

Twin Primes:

If two prime are differed by 2 then they are twin primes.

Examples: (3, 5), (5, 7), (11, 13), (17, 19), (29, 31), (41, 43) …etc

Co Primes:

If the HCF or GCD of 2 numbers is 1 then the numbers are said to be co primes.

Example:  (3, 4), (4, 5),(5, 18),(9, 20) …etc

Composite Number:

If a number is having more than 2 factors then they are called composite numbers.

Examples: 4, 6, 8, 9, 10, 12, 14, 15 … etc

Factors of 4 = 1, 2, 4.

Factors of 6 = 1, 2, 3, 6.

Factors of 8 = 1, 2, 4, 8.

Note:

1. 4 is the smallest composite number.

2. 1 is neither prime nor composite number.

Perfect Number:

If the sum of the factors of the given number is twice the given number then the number is said to be a perfect number.

Example:

1.       6 is a perfect number.

The factors of 6 are 1, 2, 3, 6.

Sum of the factors = 1+2+3+6

                            =12

                                     = 2x6