It is a dual J-K flip-flop. The CD4027B is a very common part and should be about as available as any general logic IC. I don't know of any other part that is a direct replacement.
If you're using +5V for the power supply, you can take a look at 74HC76 & 74HC113. Functionally they are similar but not pin-compatible. The Set/Reset/clock inputs are inverted too.