991111090000 has 200 divisors, whose sum is σ = 2481747586560. Its totient is φ = 383083584000.

The previous prime is 991111089971. The next prime is 991111090027. The reversal of 991111090000 is 90111199.

It is a tau number, because it is divible by the number of its divisors (200).

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 39 ways as a sum of consecutive naturals, for example, 37116654 + ... + 37143346.

Almost surely, 2^991111090000 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 991111090000, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (1240873793280).

991111090000 is an abundant number, since it is smaller than the sum of its proper divisors (1490636496560).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

991111090000 is a wasteful number, since it uses less digits than its factorization.

991111090000 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26847 (or 26826 counting only the distinct ones).

The product of its (nonzero) digits is 729, while the sum is 31.

The spelling of 991111090000 in words is "nine hundred ninety-one billion, one hundred eleven million, ninety thousand".