Alright, let's work through 77897472 times 80435487 step by step
77897472 × 80435487 = 80435487 × (77897472)
+ 80435487 × 2 yielding 160870974
+ 80435487 × 70 yielding 5630484090
+ 80435487 × 400 that is equal 32174194800
+ 80435487 × 7000 producing 563048409000
+ 80435487 × 90000 producing 7239193830000
+ 80435487 × 800000 what gives us 64348389600000
+ 80435487 × 7000000 what gives us 563048409000000
+ 80435487 × 70000000 that results in 5630484090000000

= 6265721096388864
