Alright, let's work through 1641 times 5991 step by step
1641 × 5991 = 5991 × (1641)
+ 5991 × 1 producing 5991
+ 5991 × 40 that equals 239640
+ 5991 × 600 producing 3594600
+ 5991 × 1000 that is equal 5991000

= 9831231
