It's been a long time since I've used that chip. It really depends on the crystal type and cut. Overtone SC cut crystals can't be tuned very far off. AT cut crystals can be pulled further off than SC cut crystals.
SC cut crystals are only for use in oven oscillators, and they are very difficult to use.
With AT cut crystals, the amount that they can be pulled is inversely proportional to the square of the overtone. That means that 3rd Overtone crystals have 9 times less pulling than a fundamental crystal for the same change in load.
As overtone oscillators have to be tuned to stop oscillation at other modes, it is more difficult to change the load on them.
As a result, the pulling range of overtone oscillators is extremely limited.
You won't be able to it with only that chip while using that crystal frequency. You either need to use a lower frequency crystal or cascade another divider IC after the 4521.
The max divide ratio is 2^24 which means that your minimum frequency with a 4194304hz crystal is 0.25hz which would give you 2 seconds on and 2 seconds off. You'd need a second IC.
5555???? Do you mean 555? You can't use a 555 with a crystal. At least I've never seen it done.
A 32768hz crystal would require a divide by 58,982,400 for 15min off and 15min on. The max divide on the 4521 is 16,777,216.
I used the following circuit to generate a 1Hz clock form the 60HZ power line. I added a second ÷60 section (2 more 4017s) to get a 60sec output. Hope this helps.
You calculate the period of a signal by taking the inverse of the frequency. So a 100hz waveform takes 1/100 of a second to repeat itself. A 60hz waveform takes 1/60 of a second to repeat itself, etc. You need a 30 minute period (15 on & 15 off) which is 30 x 60 = 1800 seconds long. The period of 32768hz is 30.5176 microseconds long, so 1800/0.0000305176 = 58982400 which is the divide ratio you'd need.