998990999 has 2 divisors, whose sum is σ = 998991000. Its totient is φ = 998990998.

The previous prime is 998990963. The next prime is 998991013. The reversal of 998990999 is 999099899.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 998990999 - 2¹⁶ = 998925463 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (998990959) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 499495499 + 499495500.

It is an arithmetic number, because the mean of its divisors is an integer number (499495500).

Almost surely, 2^998990999 is an apocalyptic number.

998990999 is a deficient number, since it is larger than the sum of its proper divisors (1).

998990999 is an equidigital number, since it uses as much as digits as its factorization.

998990999 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 38263752, while the sum is 71.

The square root of 998990999 is about 31606.8188687188. The cubic root of 998990999 is about 999.6635531495.

Subtracting 998990999 from its reverse (999099899), we obtain a square (108900 = 330²).

The spelling of 998990999 in words is "nine hundred ninety-eight million, nine hundred ninety thousand, nine hundred ninety-nine".