998990 has 16 divisors (see below), whose sum is σ = 1809648. Its totient is φ = 397056.

The previous prime is 998989. The next prime is 999007. The reversal of 998990 is 99899.

It is a congruent number.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 2654 + ... + 3006.

It is an arithmetic number, because the mean of its divisors is an integer number (113103).

2⁹⁹⁸⁹⁹⁰ is an apocalyptic number.

998990 is a deficient number, since it is larger than the sum of its proper divisors (810658).

998990 is a wasteful number, since it uses less digits than its factorization.

998990 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 643.

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

The square root of 998990 is about 999.4948724231. The cubic root of 998990 is about 99.9663219925.

The spelling of 998990 in words is "nine hundred ninety-eight thousand, nine hundred ninety".