2147483647 (231-1), Mersenne prime is the maximum possible value for 32-bit integer that is the largest integer that can be written in 32 bits.

What does this have to do with the phone numbers? Ironically, it has the most direct relation. It turns out that a significant number of American programmers are developing the systems in order to optimize it, where numbers are stored on the server in the form of 32-bit integers. Thus, the maximum possible number is equal to (214) 748-3647 in the United States, where 214 is a code of Dallas. When we enter into the database greater value then it is stored the maximum possible number of 2147483647.

If we conduct a search on the Internet, we can find hundreds of the phone books from all over America, which refer to the same number in Dallas. We can only sympathize to the owner of this phone number.

How could not the project’s clients to notice the mistake on the part of developers? Probably many of them did the business in the region, where the code is less than 214, so that the other phone numbers just did not get into the database. Maybe the developers convinced someone that this is the best way to optimize: in such form the numbers take up less space than when are stored in the form of individual characters. In fact many are obsessed with the optimization. The lessons of Y2K did not go well for all; moreover, a new generation of programmers grew up who do not remember Y2K at all.

via Computerworld