iTunMOVI integer

iTunes music usually comes with iTunMOVI tag, but i have a file which does not have this tag and i want to add it to the file. itunesmovi contains an integer part which we have to fill, so i was wondering how do i get the 7 digit integer number.
Eg.

<?xml version="1.0" encoding="UTF-8"?>{LF}{LF}{LF}{LF} asset-info{LF} {LF} file-size{LF} 6816527{LF} flavor{LF} 2:256{LF} {LF}{LF}{LF}

Red highlight marks the integer. so how do i get this number of a music file

If I look at the string file-size{LF} 6816527 it seems to me that it is the size of the file. So the file is around 6 MB in size.

thank you very very much. it is true