Alright, let's work through 64201977 times 77004561 step by step
64201977 × 77004561 = 77004561 × (64201977)
+ 77004561 × 7 that is equal 539031927
+ 77004561 × 70 resulting in 5390319270
+ 77004561 × 900 giving us 69304104900
+ 77004561 × 1000 giving us 77004561000
+ 77004561 × 00000 that results in 0
+ 77004561 × 200000 that equals 15400912200000
+ 77004561 × 4000000 that results in 308018244000000
+ 77004561 × 60000000 giving us 4620273660000000

= 4943845054217097
