90991000091 has 8 divisors (see below), whose sum is σ = 91898409600. Its totient is φ = 90083718400.

The previous prime is 90991000063. The next prime is 90991000109. The reversal of 90991000091 is 19000019909.

It is a happy number.

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 90991000091 - 2⁶ = 90991000027 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90991000291) 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, 2108630 + ... + 2151348.

It is an arithmetic number, because the mean of its divisors is an integer number (11487301200).

Almost surely, 2^90991000091 is an apocalyptic number.

90991000091 is a deficient number, since it is larger than the sum of its proper divisors (907409509).

90991000091 is a wasteful number, since it uses less digits than its factorization.

90991000091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 63909.

The product of its (nonzero) digits is 6561, while the sum is 38.

The spelling of 90991000091 in words is "ninety billion, nine hundred ninety-one million, ninety-one", and thus it is an aban number.