90100000991 has 32 divisors (see below), whose sum is σ = 120998954496. Its totient is φ = 64793520000.

The previous prime is 90100000943. The next prime is 90100001021. The reversal of 90100000991 is 19900000109.

It is not a de Polignac number, because 90100000991 - 2⁶ = 90100000927 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (90100000931) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 9095141 + ... + 9105041.

It is an arithmetic number, because the mean of its divisors is an integer number (3781217328).

Almost surely, 2^90100000991 is an apocalyptic number.

90100000991 is a gapful number since it is divisible by the number (91) formed by its first and last digit.

90100000991 is a deficient number, since it is larger than the sum of its proper divisors (30898953505).

90100000991 is a wasteful number, since it uses less digits than its factorization.

90100000991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19023.

The product of its (nonzero) digits is 729, while the sum is 29.

The spelling of 90100000991 in words is "ninety billion, one hundred million, nine hundred ninety-one", and thus it is an aban number.