Alright, let's work through 81100305 times 82771311 step by step
81100305 × 82771311 = 82771311 × (81100305)
+ 82771311 × 5 that equals 413856555
+ 82771311 × 00 what gives us 0
+ 82771311 × 300 producing 24831393300
+ 82771311 × 0000 which equals 0
+ 82771311 × 00000 which equals 0
+ 82771311 × 100000 that results in 8277131100000
+ 82771311 × 1000000 producing 82771311000000
+ 82771311 × 80000000 that is equal 6621704880000000

= 6712778567349855
