The frequency 32768 Hz (32.768 KHz) is commonly used, because it is a power of 2 (2^15) value. You can get a precise 1 second period (1 Hz frequency) by using a 15 stage binary counter i.e a chain of flip flops.
Having a 1Hz frequency means you have a clock signal which provides 1s time resolution. If you count the seconds with a counter, do the maths then you'll have a Real-Time Clock (RTC).
The ideal gift for a Techie who likes clocks or watches.