Alright, let's work through 85901641 times 64520871 step by step
85901641 × 64520871 = 64520871 × (85901641)
+ 64520871 × 1 what gives us 64520871
+ 64520871 × 40 what gives us 2580834840
+ 64520871 × 600 resulting in 38712522600
+ 64520871 × 1000 which equals 64520871000
+ 64520871 × 00000 producing 0
+ 64520871 × 900000 resulting in 58068783900000
+ 64520871 × 5000000 producing 322604355000000
+ 64520871 × 80000000 giving us 5161669680000000

= 5542448697649311
