Alright, let's work through 40191307 times 61890821 step by step
40191307 × 61890821 = 61890821 × (40191307)
+ 61890821 × 7 giving us 433235747
+ 61890821 × 00 yielding 0
+ 61890821 × 300 resulting in 18567246300
+ 61890821 × 1000 what gives us 61890821000
+ 61890821 × 90000 what gives us 5570173890000
+ 61890821 × 100000 resulting in 6189082100000
+ 61890821 × 0000000 which equals 0
+ 61890821 × 40000000 resulting in 2475632840000000

= 2487472987293047
