Alright, let's work through 21637684 times 21279128 step by step
21637684 × 21279128 = 21279128 × (21637684)
+ 21279128 × 4 resulting in 85116512
+ 21279128 × 80 yielding 1702330240
+ 21279128 × 600 that is equal 12767476800
+ 21279128 × 7000 giving us 148953896000
+ 21279128 × 30000 that is equal 638373840000
+ 21279128 × 600000 yielding 12767476800000
+ 21279128 × 1000000 that equals 21279128000000
+ 21279128 × 20000000 resulting in 425582560000000

= 460431047459552
