Categories of Numbers

Maths

definition

Prime Numbers

Numbers having factors and number itself are known as prime numbers.
As for example, take number .
Factors of are and
Therefore, is a prime number.

definition

Composite Numbers

Composite numbers are numbers which have at least one factor other than number itself and .
Examples of composite number are   , , .
Factors of are

definition

Perfect Numbers

Perfect numbers are positive integers that is exactly equal to the sum of its perfect positive divisors i.e. sum of positive divisors excluding the number itself.
For example :-
Divisors of  are and
Perfect divisors of   are and
And
So, is a perfect square.