Alright, let's work through 21003080 times 41154397 step by step
21003080 × 41154397 = 41154397 × (21003080)
+ 41154397 × 0 what gives us 0
+ 41154397 × 80 resulting in 3292351760
+ 41154397 × 000 yielding 0
+ 41154397 × 3000 producing 123463191000
+ 41154397 × 00000 that results in 0
+ 41154397 × 000000 yielding 0
+ 41154397 × 1000000 that equals 41154397000000
+ 41154397 × 20000000 which equals 823087940000000

= 864369092542760
