991000111111 has 8 divisors (see below), whose sum is σ = 1049387469120. Its totient is φ = 932623112448.

The previous prime is 991000111069. The next prime is 991000111133. The reversal of 991000111111 is 111111000199.

991000111111 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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

It is a cyclic number.

It is not a de Polignac number, because 991000111111 - 2¹³ = 991000102919 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 (991000171111) 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, 2392446 + ... + 2775931.

It is an arithmetic number, because the mean of its divisors is an integer number (131173433640).

Almost surely, 2^991000111111 is an apocalyptic number.

991000111111 is a deficient number, since it is larger than the sum of its proper divisors (58387358009).

991000111111 is a wasteful number, since it uses less digits than its factorization.

991000111111 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 5179673.

The product of its (nonzero) digits is 81, while the sum is 25.

The spelling of 991000111111 in words is "nine hundred ninety-one billion, one hundred eleven thousand, one hundred eleven".