990831 has 8 divisors (see below), whose sum is σ = 1390720. Its totient is φ = 625752.

The previous prime is 990809. The next prime is 990841. The reversal of 990831 is 138099.

It is a happy number.

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

It is not a de Polignac number, because 990831 - 2⁵ = 990799 is a prime.

It is a super-3 number, since 3×990831³ = 2918233322520078573, which contains 333 as substring. Note that it is a super-d number also for d = 2.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (990841) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 8635 + ... + 8748.

It is an arithmetic number, because the mean of its divisors is an integer number (173840).

2⁹⁹⁰⁸³¹ is an apocalyptic number.

990831 is a deficient number, since it is larger than the sum of its proper divisors (399889).

990831 is a wasteful number, since it uses less digits than its factorization.

990831 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 17405.

The product of its (nonzero) digits is 1944, while the sum is 30.

The square root of 990831 is about 995.4049427243. The cubic root of 990831 is about 99.6934277617.

The spelling of 990831 in words is "nine hundred ninety thousand, eight hundred thirty-one".