yea winrar also has that feature and you should be able to rejoin using it aswellYou can do it right in WinRAR.
- Right click the file you want to split
- Click "Add to Archive..."
- Under "Split to volumes, bytes" type in the size of the parts you want. Add K at the end for kilobytes, M at the end for megabytes. You can also choose autodetect or one of the defaults.