79 (number)

Seventy-nine is the natural number following 78 and preceding 80.

In mathematics

• An odd number
• The smallest number that can't be represented as a sum of fewer than 19 fourth powers
• A strictly non-palindromic number
• The 22nd prime number (the next is 83)
• The smallest prime number p for which the real quadratic field Q[√p] has class number greater than 1 (namely 3)^[1]
• A cousin prime with 83
• An emirp, because the reverse of 79, 97, is also a prime
• A fortunate prime
• A prime number that is also a Gaussian prime (since it is of the form )
• A happy prime
• A Higgs prime
• A Kynea prime ()
• A lucky prime
• A permutable prime, with ninety-seven
• A Pillai prime, because 23! + 1 is divisible by 79, but 79 is not one more than a multiple of 23
• A regular prime
• A prime in a residue classes 4n+3, 8n+7, and 10n+9
• A right-truncatable prime, because when the last digit (9) is removed, the remaining number (7) is still prime
• A sexy prime (with 73)
• The n value of the Wagstaff prime 201487636602438195784363

In science

The atomic number of the chemical element gold (Au) is 79.

In astronomy

• Messier object 79 (M79), a magnitude 8.5 globular cluster in the constellation Lepus
• New General Catalogue object 79 (NGC 79), a galaxy in the constellation Andromeda
• Saros series 79, which began on -434 May 21 and ended on 828 June 16, lasting 1262.1 years, and with 71 lunar eclipses
• Saros series 79, which began on -150 February 16 and ended on 1166 April 12, lasting 1316.2 years, and with 74 lunar eclipses

In other fields

• Live Seventy Nine, an album by Hawkwind
• The years 79 AD (or CE), 79 BC(E), or 1979
• Any of several highways numbered 79
• The record cumulative weeks at #1 on the Billboard charts, held by Elvis Presley
• The number of the French department Deux-Sèvres

References