86

86 (eighty-six) is the natural number following 85 and preceding 87. In mathematics 86 is: nontotient and a noncototient. the 25th distinct semiprime and the 13th of the form (2.q). together with 85 and 87, forms the middle semiprime in the 2nd cluster of three consecutive semiprimes; the first comprising 33, 34, 35. an Erdős–Woods number, since it is possible to find sequences of 86 consecutive integers such that each inner member shares a factor with either the first or the last member. a happy number and a self number in base 10. with an aliquot sum of 46; itself a semiprime, within an aliquot sequence of seven members (86,46,26,16,15,9,4,3,1,0) in the Prime 3-aliquot tree. It appears in the Padovan sequence, preceded by the terms 37, 49, 65 (it is the sum of the first two of these).