991807115 has 16 divisors (see below), whose sum is σ = 1357116768. Its totient is φ = 689327616.

The previous prime is 991807111. The next prime is 991807129. The reversal of 991807115 is 511708199.

It is a cyclic number.

It is not a de Polignac number, because 991807115 - 2² = 991807111 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (991807111) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 447677 + ... + 449886.

It is an arithmetic number, because the mean of its divisors is an integer number (84819798).

Almost surely, 2^991807115 is an apocalyptic number.

991807115 is a deficient number, since it is larger than the sum of its proper divisors (365309653).

991807115 is a wasteful number, since it uses less digits than its factorization.

991807115 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 897598.

The product of its (nonzero) digits is 22680, while the sum is 41.

The square root of 991807115 is about 31492.9692947489. The cubic root of 991807115 is about 997.2615460486.

The spelling of 991807115 in words is "nine hundred ninety-one million, eight hundred seven thousand, one hundred fifteen".