18002809 has 4 divisors (see below), whose sum is σ = 19639440. Its totient is φ = 16366180.

The previous prime is 18002807. The next prime is 18002837. The reversal of 18002809 is 90820081.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 18002809 - 2¹ = 18002807 is a prime.

It is a super-2 number, since 2×18002809² = 648202263780962, which contains 22 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18002807) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 818299 + ... + 818320.

It is an arithmetic number, because the mean of its divisors is an integer number (4909860).

Almost surely, 2^18002809 is an apocalyptic number.

It is an amenable number.

18002809 is a deficient number, since it is larger than the sum of its proper divisors (1636631).

18002809 is a wasteful number, since it uses less digits than its factorization.

18002809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1636630.

The product of its (nonzero) digits is 1152, while the sum is 28.

The square root of 18002809 is about 4242.9717180297. The cubic root of 18002809 is about 262.0877714203.

The spelling of 18002809 in words is "eighteen million, two thousand, eight hundred nine".