Alright, let's work through 80413025 times 84873121 step by step
80413025 × 84873121 = 84873121 × (80413025)
+ 84873121 × 5 yielding 424365605
+ 84873121 × 20 that equals 1697462420
+ 84873121 × 000 which equals 0
+ 84873121 × 3000 giving us 254619363000
+ 84873121 × 10000 giving us 848731210000
+ 84873121 × 400000 producing 33949248400000
+ 84873121 × 0000000 which equals 0
+ 84873121 × 80000000 yielding 6789849680000000

= 6824904400801025
