90865809 has 24 divisors (see below), whose sum is σ = 138538400. Its totient is φ = 57231360.

The previous prime is 90865777. The next prime is 90865843. The reversal of 90865809 is 90856809.

It is not a de Polignac number, because 90865809 - 2⁵ = 90865777 is a prime.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (90865849) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 117777 + ... + 118545.

Almost surely, 2^90865809 is an apocalyptic number.

It is an amenable number.

90865809 is a deficient number, since it is larger than the sum of its proper divisors (47672591).

90865809 is a wasteful number, since it uses less digits than its factorization.

90865809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1485 (or 1482 counting only the distinct ones).

The product of its (nonzero) digits is 155520, while the sum is 45.

The square root of 90865809 is about 9532.3558997763. The cubic root of 90865809 is about 449.5729429926.

The spelling of 90865809 in words is "ninety million, eight hundred sixty-five thousand, eight hundred nine".