Alright, let's work through 81984108 times 79802253 step by step
81984108 × 79802253 = 79802253 × (81984108)
+ 79802253 × 8 that is equal 638418024
+ 79802253 × 00 that is equal 0
+ 79802253 × 100 yielding 7980225300
+ 79802253 × 4000 which equals 319209012000
+ 79802253 × 80000 yielding 6384180240000
+ 79802253 × 900000 which equals 71822027700000
+ 79802253 × 1000000 that results in 79802253000000
+ 79802253 × 80000000 producing 6384180240000000

= 6542516528595324
