263 sits in five different types of prime number:
- a balanced prime
- an irregular prime
- a Ramanujan prime
- a Chen prime
- and a safe prime.
Balanced primes are primes where there are equal sized prime gaps above and below it. Other balanced primes are 5, 53, 157, 173, 211, 257 and 263.
Irregular primes are odd primes that are not regular… regular primes are, well complicated.
Ramanujan primes and Chen primes are both named after mathematicians who worked with primes.
Safe primes are those which can be made by doubling a prime number and adding one.
There are plenty of different types of prime numbers – mostly I think because mathematicians like to name everything.
