89 (number)
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89 is a natural number that lies between 88 and 90. It is written with two digits in base ten: 8 and 9. It is a prime number, meaning it cannot be divided by any number other than 1 and itself.
The prime numbers nearest to 89 are 83 before it and 97 after it. 89 is also a member of the Fibonacci sequence, a series in which each number is the sum of the two preceding numbers: 1, 1, 2, 3, 5, 8, 13, 21, 34, 55, 89.
Mathematical properties
The sum of the digits of 89 is 8 + 9 = 17. When written in binary (base two), 89 becomes 1011001. Because it is a prime number that cannot be divided, its only divisors are two: 1 and 89.
89 is the 11th prime number starting from 2. It is also one of the rare numbers that combine two properties: being a prime number and also being a member of the Fibonacci sequence—a combination that few numbers possess.
General use
Like other small numbers, 89 is used as a general symbol: in road numbers, in year abbreviations (for example, shorthand for the year 1989), and in sports jerseys. This use has no particular mathematical meaning; it is simply a reference.