Alright, let's work through 3121931 times 1098936 step by step
3121931 × 1098936 = 1098936 × (3121931)
+ 1098936 × 1 which equals 1098936
+ 1098936 × 30 resulting in 32968080
+ 1098936 × 900 that equals 989042400
+ 1098936 × 1000 resulting in 1098936000
+ 1098936 × 20000 which equals 21978720000
+ 1098936 × 100000 that equals 109893600000
+ 1098936 × 3000000 giving us 3296808000000

= 3430802365416
