Alright, let's work through 89240521 times 64023353 step by step
89240521 × 64023353 = 64023353 × (89240521)
+ 64023353 × 1 what gives us 64023353
+ 64023353 × 20 which equals 1280467060
+ 64023353 × 500 which equals 32011676500
+ 64023353 × 0000 giving us 0
+ 64023353 × 40000 that equals 2560934120000
+ 64023353 × 200000 that results in 12804670600000
+ 64023353 × 9000000 that is equal 576210177000000
+ 64023353 × 80000000 that is equal 5121868240000000

= 5713477377886913
