What are pre-print repositories for math and physics alternative to ArXiv? Are there other widely used academic pre-print repositories other than ArXiv? My interest is especially towards mathematics and physics.

If possible, one characteristic that I'd like to find in other pre-print repositories is the possibility to update the paper without leaving the older versions online and a better organized "author page" (and, as a note, I personally don't like Research Gate or Academia.edu, which also, as far as I understand, shouldn't be considered pre-print repositories).
In mathematics and physics arXiv is by far the most used and reputable.

Of course, there are thousands other ways to self-archive your paper using not dedicated solutions (like personal website, GitHub, etc) and some general (like FigShare).

Yet, when it comes to pre-print services, they only one I am aware of is http://vixra.org/. It has policy of accepting everything; however, it has reputation of crackpotism (as arXiv is popular and editors rarely reject from it, so for the majority if researchers there is no reason to choose viXra (unless as a protest or something)).