991075 has 12 divisors (see below), whose sum is σ = 1272240. Its totient is φ = 764960.

The previous prime is 991073. The next prime is 991079. The reversal of 991075 is 570199.

It is not a de Polignac number, because 991075 - 2¹ = 991073 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991073) 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 11 ways as a sum of consecutive naturals, for example, 42 + ... + 1408.

It is an arithmetic number, because the mean of its divisors is an integer number (106020).

2⁹⁹¹⁰⁷⁵ is an apocalyptic number.

991075 is a deficient number, since it is larger than the sum of its proper divisors (281165).

991075 is a wasteful number, since it uses less digits than its factorization.

991075 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1406 (or 1401 counting only the distinct ones).

The product of its (nonzero) digits is 2835, while the sum is 31.

The square root of 991075 is about 995.5274983646. The cubic root of 991075 is about 99.7016105228.

The spelling of 991075 in words is "nine hundred ninety-one thousand, seventy-five".