991243110111 has 12 divisors (see below), whose sum is σ = 1343679200136. Its totient is φ = 649995474720.

The previous prime is 991243110103. The next prime is 991243110113. The reversal of 991243110111 is 111011342199.

It is not a de Polignac number, because 991243110111 - 2³ = 991243110103 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991243110113) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 44387436 + ... + 44409761.

It is an arithmetic number, because the mean of its divisors is an integer number (111973266678).

Almost surely, 2^991243110111 is an apocalyptic number.

991243110111 is a deficient number, since it is larger than the sum of its proper divisors (352436090025).

991243110111 is an equidigital number, since it uses as much as digits as its factorization.

991243110111 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 88797322 (or 88797261 counting only the distinct ones).

The product of its (nonzero) digits is 1944, while the sum is 33.

The spelling of 991243110111 in words is "nine hundred ninety-one billion, two hundred forty-three million, one hundred ten thousand, one hundred eleven".