Alright, let's work through 80973731 times 31306981 step by step
80973731 × 31306981 = 31306981 × (80973731)
+ 31306981 × 1 resulting in 31306981
+ 31306981 × 30 that equals 939209430
+ 31306981 × 700 giving us 21914886700
+ 31306981 × 3000 what gives us 93920943000
+ 31306981 × 70000 resulting in 2191488670000
+ 31306981 × 900000 resulting in 28176282900000
+ 31306981 × 0000000 that results in 0
+ 31306981 × 80000000 producing 2504558480000000

= 2535043057916111
