The format for permissions on UNIX filesystems is "user/group/world".
Add the following bits to achieve the combination you want:
1 = execute
2 = write
4 = read
So 7 is RWX.
First number applies to user, second to group, and third to world.
Therefore, permissions of 741 would be user rwx, group rw, and world x.
There is also a setuid bit which prefixes the permissions.
1 = Sticky (for directories only)
2 = SetGID
4 = SetUID
... it prefixes the standard rwx attibutes like so:
4755 sets rwx on user, and rx on group/world and also sets the setuid and setgid on the file as well.
I think what you probably want is 666, or read/write for u/g/w.
Also, the X attribute on directories only means "list" since directories cannot be executed. If a directory does not contain the "list" attribute, its contents cannot be enumerated.