Question

which are the composite number

Answer 1

A composite number is a natural number (a positive integer) which can be separated into smaller integer factors. For example, the following are integers: 
4 = 2 x 2 
6 = 2 x 3 
15 = 3 x 5 
16 = 2 x 2 x 2 x 2 
etc. 

A number greater than one that can NOT be split into smaller integer factors is a prime number. The following numbers are the first prime numbers: 
2, 3, 5, 7, 11, 13, 17, 19, 23, 29, ...

Answer 2

the natural numbers other than prime numbers which have more than two factors are called composite numbers.