Alright, let's work through 9990 times 6371 step by step
9990 × 6371 = 6371 × (9990)
+ 6371 × 0 that results in 0
+ 6371 × 90 yielding 573390
+ 6371 × 900 resulting in 5733900
+ 6371 × 9000 that results in 57339000

= 63646290
