How many different spelling methods are there to make a large rectangle with 18 small squares of one square centimeter? What is the circumference of the rectangle with the largest circumference

How many different spelling methods are there to make a large rectangle with 18 small squares of one square centimeter? What is the circumference of the rectangle with the largest circumference

Length and width
18 1
9 2
6 3
Perimeter 2 × (18 + 1) = 38cm