7,

>>151
There is no multiple of two which equals one million, so when it comes to a megabyte on your actual storage device a megaBYTE is 1024*1024.

https://en.wikipedia.org/wiki/Megabyte
one megabyte is one million bytes of information. This definition has been incorporated into the International System of Quantities.

However, in the computer and information technology fields, two other definitions are used that arose for historical reasons of convenience. A common usage has been to designate one megabyte as 1048576bytes (2^20 B), a measurement that conveniently expresses the binary multiples inherent in digital computer memory architectures. However, most standards bodies have deprecated this usage in favor of a set of binary prefixes,[2] in which this quantity is designated by the unit mebibyte (MiB).