There are two numbers which are greater than 21 and their LCM and HCF are 3003 and 21 respectively.  What is the sum of these numbers?

504

Product of other factors = \(\frac{LCM}{HCF}\) = \(\frac{3003}{21}\)

                                   = 143

                                         ↓

                      Factors are:  1 × 143 or 11 × 13

Sum of these numbers = (11 + 13) × 21 = 504