Alright, let's work through 10602491 times 20390512 step by step
10602491 × 20390512 = 20390512 × (10602491)
+ 20390512 × 1 that is equal 20390512
+ 20390512 × 90 producing 1835146080
+ 20390512 × 400 what gives us 8156204800
+ 20390512 × 2000 resulting in 40781024000
+ 20390512 × 00000 what gives us 0
+ 20390512 × 600000 producing 12234307200000
+ 20390512 × 0000000 giving us 0
+ 20390512 × 10000000 that equals 203905120000000

= 216190219965392
