The number 23 in and of itself has no meaning other than denoting the mathematical amount is more than 22 and less than 24. There is a theory known as the 23 enigma, which ascribes some significance to the the number 23 and has been referenced in pop culture.
William S Burroughs is thought to the earliest proponent of the 23 enigma. Burroughs, author of books like "Nova Express" and "Naked Lunch" suggested that a number of incidences he had heard and experienced linked back to the number 23. Burroughs made reference to everything from a ship captain who allegedly sailed 23 years without an accident, until finally having a tragic accident on that 23 year anniversary. Burroughs also says that he recollected the incident while hearing about the crash of a plane, which was numbered flight 23. The less anecdotal articulation of the theory makes reference to the "law of fives" which states "all things happen in fives." This applies because two and three added together amount to five.
Ultimately, there is no legitimate evidence to support this theory or the idea that the number 23 has any intrinsic significance. Most critics of the theory cite the reasoning mistakes of selection bias and confirmation bias as debunking the notion of 23 being unique. However, any unique qualities about the number 23 are no more than urban legend.