Alright, let's work through 8689 times 1580 step by step
8689 × 1580 = 1580 × (8689)
+ 1580 × 9 that equals 14220
+ 1580 × 80 which equals 126400
+ 1580 × 600 which equals 948000
+ 1580 × 8000 that equals 12640000

= 13728620
