990998 has 8 divisors (see below), whose sum is σ = 1573992. Its totient is φ = 466336.

The previous prime is 990989. The next prime is 991009. The reversal of 990998 is 899099.

It is a sphenic number, since it is the product of 3 distinct primes.

It is an Ulam number.

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 990998.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 14540 + ... + 14607.

It is an arithmetic number, because the mean of its divisors is an integer number (196749).

2⁹⁹⁰⁹⁹⁸ is an apocalyptic number.

990998 is a deficient number, since it is larger than the sum of its proper divisors (582994).

990998 is a wasteful number, since it uses less digits than its factorization.

990998 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 29166.

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

The square root of 990998 is about 995.4888246485. The cubic root of 990998 is about 99.6990284031.

The spelling of 990998 in words is "nine hundred ninety thousand, nine hundred ninety-eight".