Alright, let's work through 12876989 times 78038656 step by step
12876989 × 78038656 = 78038656 × (12876989)
+ 78038656 × 9 yielding 702347904
+ 78038656 × 80 that is equal 6243092480
+ 78038656 × 900 yielding 70234790400
+ 78038656 × 6000 yielding 468231936000
+ 78038656 × 70000 yielding 5462705920000
+ 78038656 × 800000 resulting in 62430924800000
+ 78038656 × 2000000 that equals 156077312000000
+ 78038656 × 10000000 that equals 780386560000000

= 1004902914886784
