Yes you can. In fact X2 is the first time since SONAR was 64 bit that I haven't installed both 32 and 64 bit on the same PC.
by default SONAR gets installed into its own directory tree under Cakewalk, one under Program Files (x86)/Cakewalk/Sonar X2 Producer, for 32 bit and the other under Program Files/Cakewalk/Sonar X2 Producer, for 64 bit