Alright, let's work through 21090606 times 80811680 step by step
21090606 × 80811680 = 80811680 × (21090606)
+ 80811680 × 6 which equals 484870080
+ 80811680 × 00 what gives us 0
+ 80811680 × 600 resulting in 48487008000
+ 80811680 × 0000 giving us 0
+ 80811680 × 90000 yielding 7273051200000
+ 80811680 × 000000 that results in 0
+ 80811680 × 1000000 what gives us 80811680000000
+ 80811680 × 20000000 that equals 1616233600000000

= 1704367303078080
