89

89
Basic Information
Cardinal Number	eighty-nine
Ordinal Number	eighty ninth
Roman Numeral	LXXXIX
Greek Numeral	ΠΘ´
Factorization	89
Standard Form	8.9 × 101
Different Representations
Binary Form	10110012
Ternary Form	100223
Quaternary Form	11214
Quinary Form	3245
Senary Form	2256
Septenary Form	1557
Octal Form	1318
Nonary Form	1089
Undecimal Form	8111
Duodecimal Form	7512
Tridecimal Form	6B13
Quattuordecimal Form	6514
Quindecimal Form	5E15
Hexadecimal Form	5916
Septendecimal Form	5417
Octodecimal Form	4H18
Novemdecimal Form	4D19
Vigesimal Form	4920
Unvigesimal Form	4521
Duovigesimal Form	4122
Trevigesimal Form	3K23
Quattuorvigesimal Form	3H24
Quinvigesimal Form	3E25
Hexavigesimal Form	3B26
Septenvigesimal Form	3827
Octovigesimal Form	3528
Novemvigesimal Form	3229
Trigesimal Form	2T30
Untrigesimal Form	2R31
Duotrigesimal Form	2P32
Tretrigesimal Form	2N33
Quattuortrigesimal Form	2L34
Quintrigesimal Form	2J35
Hexatrigesimal Form	2H36
Previous	83
Current	89
Next	97

89 is a prime number between 1 and 100. 89 has two factors, 1 and 89. It is the 24th prime number, and the 24th prime number from 1-100.

Proofs

• — 89 is divisible by 1.

• — 89 is not divisible by 2-88.

• — 89 is divisible by 89.

Therefore, 89 is a prime number.

As an Exponent of Mersenne Number

2⁸⁹ - 1, which is equal to 618,970,019,642,690,137,449,562,111, is a prime number and the tenth Mersenne prime.

Relationship with other odd numbers

The numbers before

• 83 is the previous prime number.
  • The difference between 89 and 83 is 6; therefore, they are sexy primes.
• 85 is a composite number; its prime factorization is 5 * 17.
• 87 is also a composite number; its prime factorization is 3 * 29.

The numbers after

• 91 is a composite number; its prime factorization is 7 * 13.
• 93 is also a composite number; its prime factorization is 3 * 31.
• 95 is yet another composite number; its prime factorization is 5 * 19.
• 97 is the next prime number.
  • The difference between 97 and 89 is 8; the largest gap between consecutive 2-digit prime numbers.

In science

• 89 is the atomic number of actinium.

Trivia

• Although 89 is not a Lychrel number in base 10, it takes an unusually large 24 iterations of the reverse-and-add process to reach a palindrome, the most out of any number less than 10,000 known to reach a palindrome. The palindrome reached, 8,813,200,023,188, is also unusually large.
• 89 is a Fibonacci prime.
• The reciprocal of 89 returns the first few Fibonacci numbers: ${\frac {1}{89}}=0.011235955...$
• 89 is a Chen prime, since 89 + 2 = 91 is a semiprime.
• 89 is a Pythagorean prime: $89=4\times 22+1.$
• There are exactly 1,000 prime numbers between 1 and 89² = 7,921.

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Prime Numbers 1-1,000