90000091 has 6 divisors (see below), whose sum is σ = 95605940. Its totient is φ = 84705696.

The previous prime is 90000089. The next prime is 90000103. The reversal of 90000091 is 19000009.

It is not a de Polignac number, because 90000091 - 2¹ = 90000089 is a prime.

It is a Duffinian number.

90000091 is a modest number, since divided by 91 gives 90 as remainder.

It is not an unprimeable number, because it can be changed into a prime (90000991) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 155421 + ... + 155998.

Almost surely, 2^90000091 is an apocalyptic number.

90000091 is a deficient number, since it is larger than the sum of its proper divisors (5605849).

90000091 is a wasteful number, since it uses less digits than its factorization.

90000091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 311453 (or 311436 counting only the distinct ones).

The product of its (nonzero) digits is 81, while the sum is 19.

The square root of 90000091 is about 9486.8377766250. The cubic root of 90000091 is about 448.1406256956.

The spelling of 90000091 in words is "ninety million, ninety-one", and thus it is an aban number and an uban number.