Alright, let's work through 3791 times 2136 step by step
3791 × 2136 = 2136 × (3791)
+ 2136 × 1 which equals 2136
+ 2136 × 90 resulting in 192240
+ 2136 × 700 that is equal 1495200
+ 2136 × 3000 producing 6408000

= 8097576
