90090009 has 16 divisors (see below), whose sum is σ = 135461440. Its totient is φ = 59162400.

The previous prime is 90089971. The next prime is 90090043. The reversal of 90090009 is 90009009.

It is not a de Polignac number, because 90090009 - 2¹² = 90085913 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (90090709) 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, 23092 + ... + 26709.

It is an arithmetic number, because the mean of its divisors is an integer number (8466340).

Almost surely, 2^90090009 is an apocalyptic number.

It is an amenable number.

90090009 is a deficient number, since it is larger than the sum of its proper divisors (45371431).

90090009 is a wasteful number, since it uses less digits than its factorization.

90090009 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49877 (or 49871 counting only the distinct ones).

The product of its (nonzero) digits is 729, while the sum is 27.

The square root of 90090009 is about 9491.5756858385. The cubic root of 90090009 is about 448.2898199763.

It can be divided in two parts, 9009000 and 9, that added together give a palindrome (9009009).

The spelling of 90090009 in words is "ninety million, ninety thousand, nine".