Alright, let's work through 86778427 times 20646378 step by step
86778427 × 20646378 = 20646378 × (86778427)
+ 20646378 × 7 which equals 144524646
+ 20646378 × 20 giving us 412927560
+ 20646378 × 400 yielding 8258551200
+ 20646378 × 8000 producing 165171024000
+ 20646378 × 70000 that equals 1445246460000
+ 20646378 × 700000 what gives us 14452464600000
+ 20646378 × 6000000 that is equal 123878268000000
+ 20646378 × 80000000 which equals 1651710240000000

= 1791660206087406
