Mine is the lowest number whose neighbors have the same number of divisors as it. (it has 4 divisors, and so do x+1 and x-1, where it is x) It’s also a Fibonacci number and a Markov number, among other things that are either just boring or too complex to explain with words. I’m going to let you figure out what number it is, although I’m sure you could figure that out just by Googling.

Type your number into Wikipedia and you’ll get pretty much all there is to know about it.