2003 AMC 10A Problem 14

Let n be the largest integer that is the product of exactly 3 distinct prime numbers d, e, and 10d+e, where d and e are single digits. What is the sum of the digits of n?

\mathrm{(A) \ } 12\qquad \mathrm{(B) \ } 15\qquad \mathrm{(C) \ } 18\qquad \mathrm{(D) \ } 21\qquad \mathrm{(E) \ } 24

Full credit goes to MAA for authoring these problems. These problems were taken on the AOPS website.