What are the factors of 21ab?

The factors of 21ab are any numbers or variables that can be multiplied together to give the expression 21ab. These factors include 1, 3, 7, 21, a, b, 3a, 7a, 21a, 3b, 7b, and 21b. Each factor can be combined in various ways to simplify or manipulate the expression containing 21ab.