991185 has 48 divisors (see below), whose sum is σ = 1897344. Its totient is φ = 439296.

The previous prime is 991181. The next prime is 991187. The reversal of 991185 is 581199.

It is not a de Polignac number, because 991185 - 2² = 991181 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991181) 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 47 ways as a sum of consecutive naturals, for example, 43084 + ... + 43106.

It is an arithmetic number, because the mean of its divisors is an integer number (39528).

2⁹⁹¹¹⁸⁵ is an apocalyptic number.

It is an amenable number.

991185 is a deficient number, since it is larger than the sum of its proper divisors (906159).

991185 is a wasteful number, since it uses less digits than its factorization.

991185 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74 (or 61 counting only the distinct ones).

The product of its digits is 3240, while the sum is 33.

The square root of 991185 is about 995.5827439244. The cubic root of 991185 is about 99.7052990332.

It can be divided in two parts, 991 and 185, that added together give a triangular number (1176 = T₄₈).

The spelling of 991185 in words is "nine hundred ninety-one thousand, one hundred eighty-five".