No problem, we've got 1603 and 1721 to multiply
1603 × 1721 = 1721 × (1603)
+ 1721 × 3 giving us 5163
+ 1721 × 00 giving us 0
+ 1721 × 600 that equals 1032600
+ 1721 × 1000 that equals 1721000

= 2758763
