Alright, let's work through 51403858 times 78673539 step by step
51403858 × 78673539 = 78673539 × (51403858)
+ 78673539 × 8 yielding 629388312
+ 78673539 × 50 what gives us 3933676950
+ 78673539 × 800 resulting in 62938831200
+ 78673539 × 3000 producing 236020617000
+ 78673539 × 00000 that is equal 0
+ 78673539 × 400000 giving us 31469415600000
+ 78673539 × 1000000 producing 78673539000000
+ 78673539 × 50000000 producing 3933676950000000

= 4044123427113462
