17

17 (seventeen) is a positive integer following 16 and preceding 18. Its ordinal form is written "17th" or "seventeenth".
== Properties ==
*17 is . It is the third \(2^{2^2}+1\).
*17 is the smallest number of clues that a puzzle can have.McGuire, G., Tugeman, B. and Civario, G. (2014). "There Is No 16-Clue Sudoku: Solving the Sudoku Minimum Number of Clues Problem via Hitting Set Enumeration". Exmerimental Mathematics, 23(2) pp. 190-217. 
*17 is associated with bad luck in Italian superstition.
*17 is the number for the French department of .
*Ironically, the prize for 2 correct final digits in the German lottery is equal to 17 euros.
== In googology ==
*In Greek-based naming systems, 17 is associated with prefix "heptadeka-", and with prefix "septendeci-" in Latin systems.
*17 is the 6th output of the Xi function, \(\Xi(6) = 17\).
== Sources ==
Category:Numbers
Category:Class 1
Category:Numbers 0-99
 
Category:Prime numbers
Category:Numbers with 1 to 2 digits