89 (number)

89 is the natural number following 88 and preceding 90.

List of numbers — Integers << 80 81 82 83 84 85 86 87 88 89 >>
Cardinal	eighty-nine
Ordinal	89th (eighty-ninth)
Factorization	<math>prime<math>
Roman numeral	LXXXIX
Binary	01011001
Hexadecimal	59

In mathematics

Eighty-nine is the 24th prime number, following 83 and preceding 97, a Sophie Germain prime, and a Fibonacci number.

Its reciprocal has a curious relationship to the Fibonacci sequence F(n):

<math>\frac{1}{89}=\sum_{n=1}^\infty{F(n)\times 10^{-(n+1)}}=0.011235955...<math>

In other fields

Eighty-nine is also:

• the atomic number of actinium (Ac)
• the model number of CBU-89 Gator, TI-89
• part of the name of the baseball team Oklahoma City 89ers (1962-1997)
• the number of the French department Yonne
• the designation of Interstate 89, a freeway that runs from New Hampshire to Vermont
• The year AD 89, 89 BC, or 1989.