Look up fifteen in Wiktionary, the free dictionary. The Fifteen, the Jacobite rising of 15 minute dinner healthy where the House of Stuart attempted to regain the throne of the United Kingdom. This disambiguation page lists articles associated with the same number. If an internal link led you here, you may wish to change the link to point directly to the intended article.
A triangular number, a hexagonal number, and a centered tetrahedral number. The number of partitions of 7. The smallest number that can be factorized using Shor’s quantum algorithm. The magic constant of the unique order-3 normal magic square. The other such number is 13. The first 15 superabundant numbers are the same as the first 15 colossally abundant numbers.
The only other number with this property is 27. If a positive definite quadratic form with integer matrix represents all positive integers up to 15, then it represents all positive integers via the 15 and 290 theorems. There are 15 monohedral convex pentagonal tilings, with 8 being edge-to-edge. There are 15 Archimedean solids and 15 Catalan solids when enantiomorphic forms are counted separately.