819 hours = 2948400
33 minutes = 1980
54 seconds

—
2950434 seconds
—

52.0 GB (55,851,049,936 bytes)

(55,851,049,936 / 2950434) = 18929 / 1024 * 8 = 147.88886232500032198652808366498

Hence the average bitrate of my mp3 collection is 147.9 kbps