Alright, let's work through 77886904 times 87438455 step by step
77886904 × 87438455 = 87438455 × (77886904)
+ 87438455 × 4 resulting in 349753820
+ 87438455 × 00 resulting in 0
+ 87438455 × 900 that equals 78694609500
+ 87438455 × 6000 yielding 524630730000
+ 87438455 × 80000 that is equal 6995076400000
+ 87438455 × 800000 that is equal 69950764000000
+ 87438455 × 7000000 producing 612069185000000
+ 87438455 × 70000000 resulting in 6120691850000000

= 6810310550493320
