Alright, let's work through 64642094 times 64543040 step by step
64642094 × 64543040 = 64543040 × (64642094)
+ 64543040 × 4 resulting in 258172160
+ 64543040 × 90 which equals 5808873600
+ 64543040 × 000 resulting in 0
+ 64543040 × 2000 producing 129086080000
+ 64543040 × 40000 that equals 2581721600000
+ 64543040 × 600000 that is equal 38725824000000
+ 64543040 × 4000000 giving us 258172160000000
+ 64543040 × 60000000 resulting in 3872582400000000

= 4172197258725760
