Alright, let's work through 6487 times 1578 step by step
6487 × 1578 = 1578 × (6487)
+ 1578 × 7 yielding 11046
+ 1578 × 80 giving us 126240
+ 1578 × 400 producing 631200
+ 1578 × 6000 producing 9468000

= 10236486
