Can a number be illegal ?? Well, I came to know about it very recently , that in fact, a few numbers are illegal…!!!

Via  Illegal prime - Wikipedia:

An illegal prime is a prime number that represents information forbidden to possess or distribute, because when interpreted a particular way, it describes a computer program which bypasses copyright protection schemes. Distribution of that program in the United States is illegal under the Digital Millennium Copyright Act. Illegal primes are a subset of illegal numbers.