989999 has 2 divisors, whose sum is σ = 990000. Its totient is φ = 989998.

The previous prime is 989981. The next prime is 990001. The reversal of 989999 is 999989.

It is a happy number.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 989999 - 2⁸ = 989743 is a prime.

Together with 990001, it forms a pair of twin primes.

It is a Chen prime.

989999 is a modest number, since divided by 999 gives 989 as remainder.

It is a self number, because there is not a number n which added to its sum of digits gives 989999.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (989909) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 494999 + 495000.

It is an arithmetic number, because the mean of its divisors is an integer number (495000).

2⁹⁸⁹⁹⁹⁹ is an apocalyptic number.

989999 is a deficient number, since it is larger than the sum of its proper divisors (1).

989999 is an equidigital number, since it uses as much as digits as its factorization.

989999 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 472392, while the sum is 53.

The square root of 989999 is about 994.9869345876. The cubic root of 989999 is about 99.6655157838.

The spelling of 989999 in words is "nine hundred eighty-nine thousand, nine hundred ninety-nine".