90009091 has 4 divisors (see below), whose sum is σ = 90717952. Its totient is φ = 89300232.

The previous prime is 90009053. The next prime is 90009119. The reversal of 90009091 is 19090009.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 19090009 = 277 ⋅68917.

It is a cyclic number.

It is not a de Polignac number, because 90009091 - 2¹⁵ = 89976323 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90009001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 354240 + ... + 354493.

It is an arithmetic number, because the mean of its divisors is an integer number (22679488).

Almost surely, 2^90009091 is an apocalyptic number.

90009091 is a deficient number, since it is larger than the sum of its proper divisors (708861).

90009091 is a wasteful number, since it uses less digits than its factorization.

90009091 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 708860.

The product of its (nonzero) digits is 729, while the sum is 28.

The square root of 90009091 is about 9487.3121061763. The cubic root of 90009091 is about 448.1555632035.

The spelling of 90009091 in words is "ninety million, nine thousand, ninety-one".