A rough guide is 1Mb per minute. You've got 32000Mb, so that's nominally 533 hours of music but let's round that down to 500 hours to allow for blank 'run out' time at the end of tracks.
Allowing 3½ minutes per song, that's about 8500 songs but it still depends upon exactly how the songs were compressed. "At least 5000 and probably quite a bit more" is about as accurate as you can really get.
^^^ That figure of 33,344 in Webbo3's post is the number of MINUTES that are theoretically available (and it's broadly in line with the 32,000 that I've suggested).