Alright, let's work through 8631 times 3959 step by step
8631 × 3959 = 3959 × (8631)
+ 3959 × 1 what gives us 3959
+ 3959 × 30 yielding 118770
+ 3959 × 600 what gives us 2375400
+ 3959 × 8000 producing 31672000

= 34170129
