Alright, let's work through 5388841 times 64246121 step by step
5388841 × 64246121 = 64246121 × (5388841)
+ 64246121 × 1 what gives us 64246121
+ 64246121 × 40 giving us 2569844840
+ 64246121 × 800 that equals 51396896800
+ 64246121 × 8000 giving us 513968968000
+ 64246121 × 80000 producing 5139689680000
+ 64246121 × 300000 that results in 19273836300000
+ 64246121 × 5000000 producing 321230605000000

= 346212130935761
