991105 has 4 divisors (see below), whose sum is σ = 1189332. Its totient is φ = 792880.

The previous prime is 991091. The next prime is 991127. The reversal of 991105 is 501199.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 501199 = 97 ⋅5167.

It can be written as a sum of positive squares in 2 ways, for example, as 767376 + 223729 = 876^2 + 473^2 .

It is not a de Polignac number, because 991105 - 2⁵ = 991073 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 991105.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 99106 + ... + 99115.

It is an arithmetic number, because the mean of its divisors is an integer number (297333).

2⁹⁹¹¹⁰⁵ is an apocalyptic number.

It is an amenable number.

991105 is a deficient number, since it is larger than the sum of its proper divisors (198227).

991105 is a wasteful number, since it uses less digits than its factorization.

991105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 198226.

The product of its (nonzero) digits is 405, while the sum is 25.

The square root of 991105 is about 995.5425656395. The cubic root of 991105 is about 99.7026165072.

The spelling of 991105 in words is "nine hundred ninety-one thousand, one hundred five".