Alright, let's work through 42721693 times 81089957 step by step
42721693 × 81089957 = 81089957 × (42721693)
+ 81089957 × 3 which equals 243269871
+ 81089957 × 90 giving us 7298096130
+ 81089957 × 600 which equals 48653974200
+ 81089957 × 1000 that equals 81089957000
+ 81089957 × 20000 what gives us 1621799140000
+ 81089957 × 700000 that equals 56762969900000
+ 81089957 × 2000000 yielding 162179914000000
+ 81089957 × 40000000 what gives us 3243598280000000

= 3464300248337201
