International Standard Book Number in 1965, has – 340 indicating the publisher, 01381 their serial number, and 8 being the check digit. This can be converted to ; the check digit does not need to be re-calculated. Since 1 January 2007, ISBNs have contained 13 digits, a format that is compatible with "Bookland" European Article Number EAN-13s. An ISBN is assigned to each edition and variation (except reprintings) of a book. For example, an ebook, a paperback, and a hardcover edition of the same book would each have a different ISBN. The ISBN is 13 digits long if assigned on or after 1 January
13 (number) In the Mayan Tzolk'in calendar, trecenas mark cycles of 13-day periods. The pyramids are also set up in 9 steps divided into 7 days and 6 nights, 13 days total. In the standard 52-card deck of playing cards there are four suits, each of 13 ranks. In a tarot card deck, XIII is the card of Death, usually picturing the Pale horse with its rider. A baker's dozen, devil's dozen, long dozen, or long measure is 13, one more than a standard dozen. 13 (number) 13 (thirteen) is the natural number following 12 and preceding 14. Strikingly folkloric aspects of