147: There are different accounts given by different people, all of whom had very good reason to know precisely how many pairs he wore. The number I heard from the most sources was 84, if I recall correctly.
The basic idea is that there’s a Kiyum Asei in each pair worn, so why not wear as many as possible? Supposedly he had reasons Al Pi Sod for the precise number he wore, but no one knows exactly what they were.