Alright, let's work through 5121 times 1646 step by step
5121 × 1646 = 1646 × (5121)
+ 1646 × 1 yielding 1646
+ 1646 × 20 what gives us 32920
+ 1646 × 100 what gives us 164600
+ 1646 × 5000 that is equal 8230000

= 8429166
