Question 105735
A composite number is a positive integer which has a positive divisor other than one or itself. 
By definition, every integer greater than one is either a prime number or a composite number. 

A couple of rules for hunting primes and composites.
If the number ends in an even digit, it is divisible by 2. (Example:314=2x157)
Add up the digits in a number and the sum is divisible by 3, the number is divisible by 3.
(Example:501, 5+0+1=6 which is divisible by 3, then 501 is divisible by 3, 501=3x167)
Ends in a 5 or 0, divisible by 5.(Example:665=5x133).

0 - neither prime nor composite 
1 - neither prime nor composite.
15 - 3x5, composite (1+5=6, ends in 5)
19 - prime
23 - prime
31 - prime
49 - 7x7, composite
55 - 5x11, composite (ends in 5)
59 - prime
87 - 3x29, composite (8+7=15)
91 - prime
97 - prime
103 - prime
105 - 3x5x7, composite (1+0+5=6, ends in 5)