991884 has 12 divisors (see below), whose sum is σ = 2314424. Its totient is φ = 330624.

The previous prime is 991883. The next prime is 991889. The reversal of 991884 is 488199.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991883) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 41317 + ... + 41340.

2⁹⁹¹⁸⁸⁴ is an apocalyptic number.

It is an amenable number.

991884 is an abundant number, since it is smaller than the sum of its proper divisors (1322540).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

991884 is a wasteful number, since it uses less digits than its factorization.

991884 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82664 (or 82662 counting only the distinct ones).

The product of its digits is 20736, while the sum is 39.

The square root of 991884 is about 995.9337327353. The cubic root of 991884 is about 99.7287314659.

The spelling of 991884 in words is "nine hundred ninety-one thousand, eight hundred eighty-four".