Alright, let's work through 73218899 times 78735109 step by step
73218899 × 78735109 = 78735109 × (73218899)
+ 78735109 × 9 that results in 708615981
+ 78735109 × 90 resulting in 7086159810
+ 78735109 × 800 what gives us 62988087200
+ 78735109 × 8000 yielding 629880872000
+ 78735109 × 10000 yielding 787351090000
+ 78735109 × 200000 what gives us 15747021800000
+ 78735109 × 3000000 which equals 236205327000000
+ 78735109 × 70000000 resulting in 5511457630000000

= 5764897993624991
