Alright, let's work through 8641 times 9579 step by step
8641 × 9579 = 9579 × (8641)
+ 9579 × 1 producing 9579
+ 9579 × 40 that equals 383160
+ 9579 × 600 what gives us 5747400
+ 9579 × 8000 that is equal 76632000

= 82772139
