Alright, let's work through 38691344 times 91080413 step by step
38691344 × 91080413 = 91080413 × (38691344)
+ 91080413 × 4 that is equal 364321652
+ 91080413 × 40 resulting in 3643216520
+ 91080413 × 300 which equals 27324123900
+ 91080413 × 1000 that results in 91080413000
+ 91080413 × 90000 yielding 8197237170000
+ 91080413 × 600000 yielding 54648247800000
+ 91080413 × 8000000 what gives us 728643304000000
+ 91080413 × 30000000 yielding 2732412390000000

= 3524023591045072
