Alright, let's work through 20544906 times 81017624 step by step
20544906 × 81017624 = 81017624 × (20544906)
+ 81017624 × 6 that equals 486105744
+ 81017624 × 00 that equals 0
+ 81017624 × 900 giving us 72915861600
+ 81017624 × 4000 yielding 324070496000
+ 81017624 × 40000 resulting in 3240704960000
+ 81017624 × 500000 yielding 40508812000000
+ 81017624 × 0000000 producing 0
+ 81017624 × 20000000 which equals 1620352480000000

= 1664499469423344
