Alright, let's work through 1604 times 8687 step by step
1604 × 8687 = 8687 × (1604)
+ 8687 × 4 which equals 34748
+ 8687 × 00 what gives us 0
+ 8687 × 600 resulting in 5212200
+ 8687 × 1000 producing 8687000

= 13933948
