What is a prime number?  Summary and Q&A
TL;DR
Prime numbers have only two factors (1 and itself), while composite numbers have more than two factors.
Questions & Answers
Q: What is a prime number?
A prime number is a counting number with exactly two factors, itself and one. Examples of prime numbers include 3, 7, and 2.
Q: What are composite numbers?
Composite numbers are counting numbers with more than two factors. Examples are 6 and 15, which have factors other than 1 and themselves.
Q: Why is 2 a special prime number?
2 is a special prime number because it is the only even prime number. It only has two factors, 2 and 1.
Q: How can we determine if a number is composite?
Apart from being an even number that is not 2, a good clue to identify composite numbers is if the number ends in a 5 or 0, but is not 5. Most numbers divisible by 5 will have these endings.
Summary & Key Takeaways

Prime numbers are counting numbers with only two factors, themselves, and one.

Examples of prime numbers are 3, 7, and 2 (which is the only even prime number).

Composite numbers have more than two factors, such as 6 and 15.