Well, that's an interesting one.
One way to check whether the value of a string is a number is:
which will work in most cases.
However, when the value of a string is something like "1E12345", you'd get an error (<MAXNUMBER>), because "exponential notation" is assumed. But in all other cases, that would work.
Would get close to determining that a value is an integer, but "00000123" would also match that pattern, so