![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/step1.JPG\")
A prime number has exactly two whole number factors, 1 and itself.
\A composite number has more than two whole number factors.
\Express the number 19 as a product of its factors.
\Write the factors of 19. \ \
\19 = 1 × 19.
\The factors of 19 are 1 and 19.
\Since 19 has exactly two factors, 1 and itself, it is a prime number.![\"\"](\"http://www.mathskey.com/userfiles/image/steps_images/solution.JPG\")
The number 19 is a prime number.