# 809

This number is a prime.

Formerly the area code for the entire Caribbean. According to the National Fraud Information Center, it has been associated with long distance phone scams.

The only three-digit circular-digit prime.

The hotel room number in the 1952 film *Don't Bother to Knock*, starring Richard Widmark and Marilyn Monroe. Marilyn's character (Nell Forbes) is a lonely blonde who has recently been released from a mental institution. [McCranie]

The smallest prime whose fourth power is zeroless pandigital (i.e., containing all digits from 1 to 9). [Gupta]

The largest prime less than 10000 such that 2^{p}-F(*p*) is also prime, where F(*p*) is the *p*th Fibonacci number. [Opao]

The lesser of the smallest twin prime pair that contain no prime digits. [Punches]

The smallest circular-digit Cyclops prime. [Punches]

809 is the start of 21 consecutive primes which alternate between the forms 6*n* - 1 and 6*n* + 1. The smallest start of 22 such primes is the much larger 3954889. [Andersen]

Largest known prime p such that T(p) is prime in Juricevic conjecture on classification of Lehmer triples. Juricevic conjectured an infinite number of such primes. Yu Tsumura proved that T(p) is infinitely often composite. [Post]

The larger of only two 3-digit distinct-digit primes whose the absolute difference between any two of its digits is a non-prime number. The other is 109. [Loungrides]