991055 has 16 divisors (see below), whose sum is σ = 1303680. Its totient is φ = 718848.

The previous prime is 991043. The next prime is 991057. The reversal of 991055 is 550199.

991055 is nontrivially palindromic in base 4.

It is not a de Polignac number, because 991055 - 2⁸ = 990799 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991057) 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, 5039 + ... + 5231.

It is an arithmetic number, because the mean of its divisors is an integer number (81480).

2⁹⁹¹⁰⁵⁵ is an apocalyptic number.

991055 is a deficient number, since it is larger than the sum of its proper divisors (312625).

991055 is a wasteful number, since it uses less digits than its factorization.

991055 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 290.

The product of its (nonzero) digits is 2025, while the sum is 29.

The square root of 991055 is about 995.5174533879. The cubic root of 991055 is about 99.7009398552.

The spelling of 991055 in words is "nine hundred ninety-one thousand, fifty-five".