18090909 has 12 divisors (see below), whose sum is σ = 26179452. Its totient is φ = 12038400.

The previous prime is 18090901. The next prime is 18090923. The reversal of 18090909 is 90909081.

It can be written as a sum of positive squares in 2 ways, for example, as 16426809 + 1664100 = 4053^2 + 1290^2 .

It is not a de Polignac number, because 18090909 - 2³ = 18090901 is a prime.

18090909 is a modest number, since divided by 90909 gives 18 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18090901) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 4429 + ... + 7469.

It is an arithmetic number, because the mean of its divisors is an integer number (2181621).

Almost surely, 2^18090909 is an apocalyptic number.

It is an amenable number.

18090909 is a deficient number, since it is larger than the sum of its proper divisors (8088543).

18090909 is a wasteful number, since it uses less digits than its factorization.

18090909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3708 (or 3705 counting only the distinct ones).

The product of its (nonzero) digits is 5832, while the sum is 36.

The square root of 18090909 is about 4253.3409221458. The cubic root of 18090909 is about 262.5146005484.

The spelling of 18090909 in words is "eighteen million, ninety thousand, nine hundred nine".