Alright, let's work through 521689 times 87701020 step by step
521689 × 87701020 = 87701020 × (521689)
+ 87701020 × 9 resulting in 789309180
+ 87701020 × 80 yielding 7016081600
+ 87701020 × 600 that is equal 52620612000
+ 87701020 × 1000 what gives us 87701020000
+ 87701020 × 20000 giving us 1754020400000
+ 87701020 × 500000 what gives us 43850510000000

= 45752657422780
