As I understand it, an irrational meter is when the bottom number on the time signature is not a power of 2, i.e. 1,2,4,8,16, 32, etc. An example irrational meter that I've seen is 5/24. According to Wikpedia:
Irrational time signatures (rarely, "non-dyadic time signatures") are used for so-called irrational bar lengths, that have a denominator that is not a power of two (1, 2, 4, 8, 16, 32, etc.). These are based on beats expressed in terms of fractions of full beats in the prevailing tempo—for example 3/10 or 5/24
Can any positive integer be used for irrational meters or are there certain restrictions?