90090990991 has 16 divisors (see below), whose sum is σ = 93382279200. Its totient is φ = 86874697728.

The previous prime is 90090990959. The next prime is 90090991009. The reversal of 90090990991 is 19909909009.

It is a happy number.

It is a cyclic number.

It is not a de Polignac number, because 90090990991 - 2⁵ = 90090990959 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 (90090990911) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 577045 + ... + 716353.

It is an arithmetic number, because the mean of its divisors is an integer number (5836392450).

Almost surely, 2^90090990991 is an apocalyptic number.

90090990991 is a deficient number, since it is larger than the sum of its proper divisors (3291288209).

90090990991 is a wasteful number, since it uses less digits than its factorization.

90090990991 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139578.

The product of its (nonzero) digits is 531441, while the sum is 55.

The spelling of 90090990991 in words is "ninety billion, ninety million, nine hundred ninety thousand, nine hundred ninety-one".