9767

9767 is a prime number.

9767 is the largest four-digit prime formed by the concatenation of two two-digit primes.

9767 and 9769 form a twin prime pair.

9767 is 14352 in base 9 (using each of the digits from 1 to 5 once).

9767 is the upper prime of a difference of 18 between consecutive primes (A031937).

9767 cannot be written as a sum of three squares.

Source: Number Gossip