Alright, let's work through 81720359 times 71138446 step by step
81720359 × 71138446 = 71138446 × (81720359)
+ 71138446 × 9 that equals 640246014
+ 71138446 × 50 giving us 3556922300
+ 71138446 × 300 that is equal 21341533800
+ 71138446 × 0000 giving us 0
+ 71138446 × 20000 that is equal 1422768920000
+ 71138446 × 700000 producing 49796912200000
+ 71138446 × 1000000 what gives us 71138446000000
+ 71138446 × 80000000 resulting in 5691075680000000

= 5813459345822114
