Alright, let's work through 6421 times 3101 step by step
6421 × 3101 = 3101 × (6421)
+ 3101 × 1 producing 3101
+ 3101 × 20 giving us 62020
+ 3101 × 400 what gives us 1240400
+ 3101 × 6000 which equals 18606000

= 19911521
