Alright, let's work through 18121245 times 83339243 step by step
18121245 × 83339243 = 83339243 × (18121245)
+ 83339243 × 5 which equals 416696215
+ 83339243 × 40 that results in 3333569720
+ 83339243 × 200 that is equal 16667848600
+ 83339243 × 1000 yielding 83339243000
+ 83339243 × 20000 yielding 1666784860000
+ 83339243 × 100000 what gives us 8333924300000
+ 83339243 × 8000000 which equals 666713944000000
+ 83339243 × 10000000 which equals 833392430000000

= 1510210840517535
