991109111 has 8 divisors (see below), whose sum is σ = 999222000. Its totient is φ = 983016000.

The previous prime is 991109089. The next prime is 991109149. The reversal of 991109111 is 111901199.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-991109111 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (991109011) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 105611 + ... + 114611.

It is an arithmetic number, because the mean of its divisors is an integer number (124902750).

Almost surely, 2^991109111 is an apocalyptic number.

991109111 is a deficient number, since it is larger than the sum of its proper divisors (8112889).

991109111 is a wasteful number, since it uses less digits than its factorization.

991109111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9889.

The product of its (nonzero) digits is 729, while the sum is 32.

The square root of 991109111 is about 31481.8854422666. The cubic root of 991109111 is about 997.0275435906.

The spelling of 991109111 in words is "nine hundred ninety-one million, one hundred nine thousand, one hundred eleven".