2311

2311 is a prime number.

2309 and 2311 form a twin prime pair.

2311 is the largest member in a set of twin primes generated by the formula 30(n*(n + 5)/2) + 60 +1 and - 1, for n = 1 to 10.

2311 is the concatenation of the first three prime Ulam numbers (2, 3, 11).

2311 is a Euclid number.

2311 is 4407 in base 8 and 1407 in base 12. It is 907 in base 16 and 727 in base 18.

2311 is a divisor of 41²² - 1.

November 23 is the only date that can be read as a prime in both formats: "day-month" (2311) or "month-day" (1123).

Source: Prime Curios!