Alright, let's work through 16390863 times 6837379 step by step
16390863 × 6837379 = 6837379 × (16390863)
+ 6837379 × 3 that results in 20512137
+ 6837379 × 60 what gives us 410242740
+ 6837379 × 800 what gives us 5469903200
+ 6837379 × 0000 what gives us 0
+ 6837379 × 90000 resulting in 615364110000
+ 6837379 × 300000 that results in 2051213700000
+ 6837379 × 6000000 yielding 41024274000000
+ 6837379 × 10000000 giving us 68373790000000

= 112070542468077
