What is the positive difference between the product of the four smallest prime numbers and the product of the four smallest composite numbers greater than 0?
The four smallest prime numbers are 2, 3, 5, and 7, with product $2 \cdot 3 \cdot 5 \cdot 7 = 210$.  The four smallest composite numbers are 4, 6, 8, and 9, with product $4 \cdot 6 \cdot 8 \cdot 9 = 1728$.  The positive difference is thus $1728 - 210 = \boxed{1518}$.