This number is a prime.

+ The largest known prime whose square is strobogrammatic.

+ Anne Frank and seven others hid from the Nazis in an annex behind the house at Prinsengracht 263 in Amsterdam.

+ The length of the longest human chromosome in millions of nucleotide pairs. [Faulds]

+ The number of digits in 263!2 (double factorial). Note that 263 is the only prime with this property. [Firoozbakht]

+ 263 is the smallest prime number which is sum of primes beginning and ending with the digit 1. Note that the digit sum of each prime is prime and that the digit sum of 263 is beginning and ending with the digit 1: 263 = 11 + 101 + 151. [Capelle]

+ The smallest prime formed by inserting a semiprime between the semiprime's factors. The sequence of such primes begins 263, 3217, 22613, 33311, etc. [Honaker]

+ The middle prime in the only set of three 3-digit primes that contain all of the digits 1 through 9, and whose sum is a 3-digit number. [Gardner]

+ The turbocharged Mazdaspeed3 generates 263 horsepower. [Hubbard]

+ In August 2007, mathematician Ali Nesin was jailed under Article TCK 263 of Turkish Criminal Code (running an illegal educational institution) for conducting a mathematics summer camp. [Caldwell]

+ The number of congresspersons in the United States House of Representatives that voted yes on October 3, 2008, to pass an amended government bailout of Wall Street firms.

+ According to the Internet Movie Database, only 1/263rd of the film taken of the chariot race in the 1959 epic movie Ben Hur was actually used in the final cut. [Caldwell]

+ The smallest Honaker prime that is a balanced prime. It is also the smallest Honaker prime p for which q=p^3+2 is an emirp (q=18191449). [Loungrides]

+ The only prime with three distinct digits, where one is the product of the other two. [Silva]

+ The least prime whose square divides some number of the form q#/p#+p#, where p,q are primes (263^2 divides 199#/7#+7#). [Wallrodt]

+ The only 3-digit prime whose the square, 69169, is a strobogrammatic number. Likely, 263 is the largest known prime with this property. [Loungrides]

+ The smallest Happy Honaker prime. [Gaydos]

+ TRUMP INTERNATIONAL HOTEL WASHINGTON, D.C., contains 263 luxury guest rooms and suites.

(There are 10 curios for this number that have not yet been approved by an editor.)

Printed from the PrimePages <t5k.org> © G. L. Honaker and Chris K. Caldwell