Alright, let's work through 2407 times 6391 step by step
2407 × 6391 = 6391 × (2407)
+ 6391 × 7 producing 44737
+ 6391 × 00 giving us 0
+ 6391 × 400 yielding 2556400
+ 6391 × 2000 yielding 12782000

= 15383137
