Answer: 19
Definition:
Prime: Prime numbers are numbers that can only be multiplied ONE time.
Example: 19×1=19
Composite: Composite numbers are numbers that can be multiplied MORE THAN ONE time.
Number 15: 15×1=15, 15×2=30, 15×3=45
Number 18: 18×1=18, 18×2=36, 18×3=54
Number 22: 22×1=22, 22×2=44, 22×3=66
