991890290108 has 24 divisors (see below), whose sum is σ = 1795772193600. Its totient is φ = 478814591808.

The previous prime is 991890290089. The next prime is 991890290119. The reversal of 991890290108 is 801092098199.

It is a super-2 number, since 2×991890290108² (a number of 25 digits) contains 22 as substring.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1730573 + ... + 2231291.

It is an arithmetic number, because the mean of its divisors is an integer number (74823841400).

Almost surely, 2^991890290108 is an apocalyptic number.

It is an amenable number.

991890290108 is a deficient number, since it is larger than the sum of its proper divisors (803881903492).

991890290108 is a wasteful number, since it uses less digits than its factorization.

991890290108 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 517829 (or 517827 counting only the distinct ones).

The product of its (nonzero) digits is 839808, while the sum is 56.

The spelling of 991890290108 in words is "nine hundred ninety-one billion, eight hundred ninety million, two hundred ninety thousand, one hundred eight".