18645809 has 16 divisors (see below), whose sum is σ = 23331840. Its totient is φ = 14506560.

The previous prime is 18645799. The next prime is 18645841. The reversal of 18645809 is 90854681.

It is a cyclic number.

It is not a de Polignac number, because 18645809 - 2¹² = 18641713 is a prime.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (18642809) 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, 3872 + ... + 7230.

It is an arithmetic number, because the mean of its divisors is an integer number (1458240).

Almost surely, 2^18645809 is an apocalyptic number.

It is an amenable number.

18645809 is a deficient number, since it is larger than the sum of its proper divisors (4686031).

18645809 is a wasteful number, since it uses less digits than its factorization.

18645809 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 3440.

The product of its (nonzero) digits is 69120, while the sum is 41.

The square root of 18645809 is about 4318.0793184007. The cubic root of 18645809 is about 265.1716415028.

The spelling of 18645809 in words is "eighteen million, six hundred forty-five thousand, eight hundred nine".