Alright, let's work through 64486999 times 65261148 step by step
64486999 × 65261148 = 65261148 × (64486999)
+ 65261148 × 9 yielding 587350332
+ 65261148 × 90 giving us 5873503320
+ 65261148 × 900 that equals 58735033200
+ 65261148 × 6000 producing 391566888000
+ 65261148 × 80000 that results in 5220891840000
+ 65261148 × 400000 yielding 26104459200000
+ 65261148 × 4000000 producing 261044592000000
+ 65261148 × 60000000 that is equal 3915668880000000

= 4208495585814852
