99989 has 2 divisors, whose sum is σ = 99990. Its totient is φ = 99988.

The previous prime is 99971. The next prime is 99991. The reversal of 99989 is 98999.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 52900 + 47089 = 230^2 + 217^2 .

It is an emirp because it is prime and its reverse (98999) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 99989 - 2⁸ = 99733 is a prime.

Together with 99991, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99929) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49994 + 49995.

It is an arithmetic number, because the mean of its divisors is an integer number (49995).

2⁹⁹⁹⁸⁹ is an apocalyptic number.

It is an amenable number.

99989 is a deficient number, since it is larger than the sum of its proper divisors (1).

99989 is an equidigital number, since it uses as much as digits as its factorization.

99989 is an evil number, because the sum of its binary digits is even.

The product of its digits is 52488, while the sum is 44.

The square root of 99989 is about 316.2103730114. The cubic root of 99989 is about 46.4141863578.

Subtracting from 99989 its reverse (98999), we obtain a triangular number (990 = T₄₄).

The spelling of 99989 in words is "ninety-nine thousand, nine hundred eighty-nine".