Can someone explain to me what prime numbers are?

A prime number is a number greater than one and can only be divided by 1 and itself. The result is always a whole number, i.e. no fractions, decimals, remainders. 

Example: 
2 can only be divided by 1 and itself 
3 can only be divided by 1 and itself. 

4 however, can be divided by 1 or 2 or itself 

1 is not a prime number since it is not greater than one.

Prime numbers are positive integers that cannot be factored. Meaning it cannot be divided by any other number but 1 and itself.

For example:
2 is a prime number. It can only be divided by 1 and 2.
4 is not a prime number. Because it can be divided by 1, 2, and 4.

Take note: prime numbers are POSITIVE integers only.

Additional information about prime numbers:
* The only even prime number is 2. The rest even number are not prime numbers because it can be divided by 2.
* zero and 1 are not considered prime numbers
* numbers that are not prime numbers are called composite numbers.