983991 has 16 divisors (see below), whose sum is σ = 1408640. Its totient is φ = 609120.

The previous prime is 983987. The next prime is 983993. The reversal of 983991 is 199389.

It is not a de Polignac number, because 983991 - 2² = 983987 is a prime.

It is a super-3 number, since 3×983991³ = 2858213283981333813, which contains 333 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (983993) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3336 + ... + 3618.

It is an arithmetic number, because the mean of its divisors is an integer number (88040).

2⁹⁸³⁹⁹¹ is an apocalyptic number.

983991 is a deficient number, since it is larger than the sum of its proper divisors (424649).

983991 is a wasteful number, since it uses less digits than its factorization.

983991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 366.

The product of its digits is 17496, while the sum is 39.

The square root of 983991 is about 991.9632049628. The cubic root of 983991 is about 99.4634934212.

The spelling of 983991 in words is "nine hundred eighty-three thousand, nine hundred ninety-one".