Alright, let's work through 81961134 times 64590033 step by step
81961134 × 64590033 = 64590033 × (81961134)
+ 64590033 × 4 yielding 258360132
+ 64590033 × 30 producing 1937700990
+ 64590033 × 100 that equals 6459003300
+ 64590033 × 1000 which equals 64590033000
+ 64590033 × 60000 yielding 3875401980000
+ 64590033 × 900000 giving us 58131029700000
+ 64590033 × 1000000 giving us 64590033000000
+ 64590033 × 80000000 producing 5167202640000000

= 5293872349777422
