Alright, let's work through 3864 times 2591 step by step
3864 × 2591 = 2591 × (3864)
+ 2591 × 4 producing 10364
+ 2591 × 60 that equals 155460
+ 2591 × 800 that is equal 2072800
+ 2591 × 3000 that is equal 7773000

= 10011624
