991156 has 18 divisors (see below), whose sum is σ = 1792518. Its totient is φ = 479520.

The previous prime is 991147. The next prime is 991171. The reversal of 991156 is 651199.

It can be written as a sum of positive squares in 3 ways, for example, as 234256 + 756900 = 484^2 + 870^2 .

It is a congruent number.

It is an unprimeable number.

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 5 ways as a sum of consecutive naturals, for example, 5386 + ... + 5566.

2⁹⁹¹¹⁵⁶ is an apocalyptic number.

It is an amenable number.

991156 is a deficient number, since it is larger than the sum of its proper divisors (801362).

991156 is a wasteful number, since it uses less digits than its factorization.

991156 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 259 (or 220 counting only the distinct ones).

The product of its digits is 2430, while the sum is 31.

The square root of 991156 is about 995.5681794835. The cubic root of 991156 is about 99.7043266342.

The spelling of 991156 in words is "nine hundred ninety-one thousand, one hundred fifty-six".