998689 has 2 divisors, whose sum is σ = 998690. Its totient is φ = 998688.

The previous prime is 998687. The next prime is 998717. The reversal of 998689 is 986899.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 966289 + 32400 = 983^2 + 180^2 .

It is a cyclic number.

It is not a de Polignac number, because 998689 - 2¹ = 998687 is a prime.

Together with 998687, it forms a pair of twin primes.

998689 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (998681) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499344 + 499345.

It is an arithmetic number, because the mean of its divisors is an integer number (499345).

2⁹⁹⁸⁶⁸⁹ is an apocalyptic number.

It is an amenable number.

998689 is a deficient number, since it is larger than the sum of its proper divisors (1).

998689 is an equidigital number, since it uses as much as digits as its factorization.

998689 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 279936, while the sum is 49.

The square root of 998689 is about 999.3442850189. The cubic root of 998689 is about 99.9562808892.

The spelling of 998689 in words is "nine hundred ninety-eight thousand, six hundred eighty-nine".