18239309 has 4 divisors (see below), whose sum is σ = 19897440. Its totient is φ = 16581180.

The previous prime is 18239303. The next prime is 18239311. The reversal of 18239309 is 90393281.

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 not a de Polignac number, because 18239309 - 2⁴ = 18239293 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18239303) 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, 829049 + ... + 829070.

It is an arithmetic number, because the mean of its divisors is an integer number (4974360).

Almost surely, 2^18239309 is an apocalyptic number.

It is an amenable number.

18239309 is a deficient number, since it is larger than the sum of its proper divisors (1658131).

18239309 is a wasteful number, since it uses less digits than its factorization.

18239309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1658130.

The product of its (nonzero) digits is 11664, while the sum is 35.

The square root of 18239309 is about 4270.7504024469. The cubic root of 18239309 is about 263.2304504716.

The spelling of 18239309 in words is "eighteen million, two hundred thirty-nine thousand, three hundred nine".