Why is the clock crystal 32.768KHz 15 divided?

Real-time Clock crystal why the choice is 32768Hz Crystal, Baidu on the most of the answer is to say that 32768 is 2 of the 15-square, convenient crossover to get accurate 1 seconds. But the words came back, 2 of the whole number of reasons why the choice of 15?

1. The higher the frequency, the higher the accuracy, the less error.

2. There are also deviations between the actual frequency of each crystal oscillator and its nominal frequency for various reasons.

3. The working environment of crystal Oscillator also has influence on the frequency of crystal oscillator, and the frequency stability of crystal oscillator is used to indicate the size of different crystal oscillator affected by the environment, its unit is ppm (one out of 10,000)

4. Accurate timing commonly used 32.768KHz crystal oscillator reason: 2 of the 15 is 32768, using this frequency of crystal oscillator, people can easily through the crossover circuit to get 1Hz of the time pulse; usually the higher the operating frequency, the larger the power consumption of digital circuit such as MCU, 32.768KHz this frequency is relatively low, it is advantageous to reduce the circuit power consumption.

32768Hz should be the 1th and 4th compromise choice!

Why is the clock crystal 32.768KHz 15 divided?