99 is the natural number following 98 and preceding 100.

Cardinal	ninety-nine
Ordinal	99th (ninety-ninth)
Factorization
Divisors	3, 9, 11, 33
Roman numeral	XCIX
Binary	1100011
Hexadecimal	63

In mathematics

Ninety-nine is the ninth repdigit, a palindromic number and a Kaprekar number.

In science

• The atomic number of einsteinium, an actinide.

In astronomy,

Messier object M99, a magnitude 10.5 spiral galaxy in the constellation Coma Berenices

The New General Catalogue object NGC 99 , a magnitude 13.7 spiral galaxy in the constellation Pisces

The Saros number of the solar eclipse series which began on 235 June 3 and ended on 1515 July 11. The duration of Saros series 99 was 1280.1 years, and it contained 72 solar eclipses.

The Saros number of the lunar eclipse series which began on 55 March 24 and ended on 1835 May 12. The duration of Saros series 99 was 1280.1 years, and it contained 72 lunar eclipses.

In other fields

Ninety-nine is also:

• Often used as a qualifier for something which is almost but not quite certain: "Ninety-nine per cent sure."
• The designation of American Interstate 99, a freeway in Pennsylvania, planned to be extended into New York.
• A card game.
• In the TV show Get Smart, the codename of Agent 99.
• The uniform number of retired NHL player Wayne Gretzky, retired MLB closer Mitch Williams, and fictional pitcher Rick "Wild Thing" Vaughn (played by Charlie Sheen) in the 1989 David S. Ward film Major League, among many other athletes.
• The year AD 99, 99 BC, or 1999.
• Another name for the 99 Flake, a popular kind of ice cream cone.
• The name of the Australian indie band ninetynine.
• The name of a Japanese comedy duo best known for their show Mecha Mecha Iketeru .
• The name of the New England chain Ninety-Nine Restaurant and Pub .
• Number of balloons in early 1980s German pos song by Nena, Neunundneunzig luftballons (English version 99 red balloons performed by Goldfinger
• In Stephen King's Dark Tower series, 99 is also a number of magical signifigance. It is eluding to June 19, 1999, where the Crimson King conspires to end Stephen King's life so that the Dark Tower will fall and time will be destroyed. See the 19 ( number) article for further information.