Alright, let's work through 66885965 times 65838556 step by step
66885965 × 65838556 = 65838556 × (66885965)
+ 65838556 × 5 what gives us 329192780
+ 65838556 × 60 that is equal 3950313360
+ 65838556 × 900 resulting in 59254700400
+ 65838556 × 5000 resulting in 329192780000
+ 65838556 × 80000 what gives us 5267084480000
+ 65838556 × 800000 that is equal 52670844800000
+ 65838556 × 6000000 that results in 395031336000000
+ 65838556 × 60000000 which equals 3950313360000000

= 4403675352266540
