Alright, let's work through 1587 times 8365 step by step
1587 × 8365 = 8365 × (1587)
+ 8365 × 7 resulting in 58555
+ 8365 × 80 resulting in 669200
+ 8365 × 500 that results in 4182500
+ 8365 × 1000 what gives us 8365000

= 13275255
