Alright, let's work through 3651 times 3872 step by step
3651 × 3872 = 3872 × (3651)
+ 3872 × 1 what gives us 3872
+ 3872 × 50 which equals 193600
+ 3872 × 600 that results in 2323200
+ 3872 × 3000 that is equal 11616000

= 14136672
