990931 has 4 divisors (see below), whose sum is σ = 998200. Its totient is φ = 983664.

The previous prime is 990923. The next prime is 990953. The reversal of 990931 is 139099.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 139099 = 19 ⋅7321.

It is a cyclic number.

It is not a de Polignac number, because 990931 - 2³ = 990923 is a prime.

It is a super-2 number, since 2×990931² = 1963888493522, which contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 990893 and 990902.

It is not an unprimeable number, because it can be changed into a prime (990961) 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 in 3 ways as a sum of consecutive naturals, for example, 3426 + ... + 3703.

It is an arithmetic number, because the mean of its divisors is an integer number (249550).

2⁹⁹⁰⁹³¹ is an apocalyptic number.

990931 is a deficient number, since it is larger than the sum of its proper divisors (7269).

990931 is a wasteful number, since it uses less digits than its factorization.

990931 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7268.

The product of its (nonzero) digits is 2187, while the sum is 31.

The square root of 990931 is about 995.4551722705. The cubic root of 990931 is about 99.6967815148.

The spelling of 990931 in words is "nine hundred ninety thousand, nine hundred thirty-one".