Alright, let's work through 9877 times 1641 step by step
9877 × 1641 = 1641 × (9877)
+ 1641 × 7 that equals 11487
+ 1641 × 70 that is equal 114870
+ 1641 × 800 yielding 1312800
+ 1641 × 9000 that is equal 14769000

= 16208157
