Alright, let's work through 63521376 times 61398332 step by step
63521376 × 61398332 = 61398332 × (63521376)
+ 61398332 × 6 that equals 368389992
+ 61398332 × 70 that results in 4297883240
+ 61398332 × 300 what gives us 18419499600
+ 61398332 × 1000 giving us 61398332000
+ 61398332 × 20000 that equals 1227966640000
+ 61398332 × 500000 which equals 30699166000000
+ 61398332 × 3000000 that equals 184194996000000
+ 61398332 × 60000000 what gives us 3683899920000000

= 3900106532744832
