Alright, let's work through 84401591 times 64052141 step by step
84401591 × 64052141 = 64052141 × (84401591)
+ 64052141 × 1 what gives us 64052141
+ 64052141 × 90 what gives us 5764692690
+ 64052141 × 500 yielding 32026070500
+ 64052141 × 1000 yielding 64052141000
+ 64052141 × 00000 producing 0
+ 64052141 × 400000 that equals 25620856400000
+ 64052141 × 4000000 which equals 256208564000000
+ 64052141 × 80000000 that equals 5124171280000000

= 5406102607356331
