18091809 has 32 divisors (see below), whose sum is σ = 27776640. Its totient is φ = 11632896.

The previous prime is 18091793. The next prime is 18091813. The reversal of 18091809 is 90819081.

It is not a de Polignac number, because 18091809 - 2⁴ = 18091793 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18091849) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 131989 + ... + 132125.

It is an arithmetic number, because the mean of its divisors is an integer number (868020).

Almost surely, 2^18091809 is an apocalyptic number.

It is an amenable number.

18091809 is a deficient number, since it is larger than the sum of its proper divisors (9684831).

18091809 is a wasteful number, since it uses less digits than its factorization.

18091809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 286 (or 280 counting only the distinct ones).

The product of its (nonzero) digits is 5184, while the sum is 36.

The square root of 18091809 is about 4253.4467200143. The cubic root of 18091809 is about 262.5189537335.

The spelling of 18091809 in words is "eighteen million, ninety-one thousand, eight hundred nine".