99689 has 2 divisors, whose sum is σ = 99690. Its totient is φ = 99688.

The previous prime is 99679. The next prime is 99707. The reversal of 99689 is 98699.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 80089 + 19600 = 283^2 + 140^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-99689 is a prime.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (99679) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 49844 + 49845.

It is an arithmetic number, because the mean of its divisors is an integer number (49845).

2⁹⁹⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

99689 is a deficient number, since it is larger than the sum of its proper divisors (1).

99689 is an equidigital number, since it uses as much as digits as its factorization.

99689 is an evil number, because the sum of its binary digits is even.

The product of its digits is 34992, while the sum is 41.

The square root of 99689 is about 315.7356489217. The cubic root of 99689 is about 46.3677205634.

Subtracting from 99689 its reverse (98699), we obtain a triangular number (990 = T₄₄).

The spelling of 99689 in words is "ninety-nine thousand, six hundred eighty-nine".