991355 has 16 divisors (see below), whose sum is σ = 1283040. Its totient is φ = 732672.

The previous prime is 991343. The next prime is 991357. The reversal of 991355 is 553199.

It is a cyclic number.

It is not a de Polignac number, because 991355 - 2¹⁰ = 990331 is a prime.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 991355.

It is not an unprimeable number, because it can be changed into a prime (991357) by changing a digit.

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 15 ways as a sum of consecutive naturals, for example, 9041 + ... + 9149.

It is an arithmetic number, because the mean of its divisors is an integer number (80190).

2⁹⁹¹³⁵⁵ is an apocalyptic number.

991355 is a deficient number, since it is larger than the sum of its proper divisors (291685).

991355 is a wasteful number, since it uses less digits than its factorization.

991355 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 238.

The product of its digits is 6075, while the sum is 32.

The square root of 991355 is about 995.6681173966. The cubic root of 991355 is about 99.7109989217.

The spelling of 991355 in words is "nine hundred ninety-one thousand, three hundred fifty-five".