For example one can have the number 0.12 and can look at the sequence of the digits of it's internal decimal places and see, that 0.12 contains the numbers 1,2 and 12. It is also easy to construct a number, that contain all natural numbers by just numerating the natural numbers and write them one after the other behind the 0. . However I was wondering, if it were possible to find all natural numbers in beautiful numbers like Pi or e or $ \sqrt2 $ etc. , also if this is some sort of property only a few numbers share.

Can anyone recommend some sort of reading material on that topic or knows more about it? As always: Many thanks in advance.