The side length is 6, and the surface area should be 6*6*6=2 16 (square centimeter).

Because each side has a cube hole with a side length of 2 cm, but the area of each small cube should be 4 sides, the total area of the small cube should be 2*2*4*6=96 (square centimeter), plus the original 2 16 (square centimeter), so the total surface area should be 2 16+96.