I don't see any secrets. They are all numbers of decimal numbering system. All three of these numbers are odd numbers. That means they are not divisible by two. According to wiki:
> In mathematics, parity is the property of an integer's inclusion in one of two categories: even or odd. An integer is even if it is evenly divisible by two and odd if it is not even. For example, 6 is even because there is no remainder when dividing it by 2.
> https://en.wikipedia.org/wiki/Parity_(mathematics)
