18209138 has 8 divisors (see below), whose sum is σ = 27363420. Its totient is φ = 9088000.

The previous prime is 18209137. The next prime is 18209161. The reversal of 18209138 is 83190281.

It can be written as a sum of positive squares in 2 ways, for example, as 18207289 + 1849 = 4267^2 + 43^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not an unprimeable number, because it can be changed into a prime (18209137) 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, 6863 + ... + 9138.

Almost surely, 2^18209138 is an apocalyptic number.

18209138 is a deficient number, since it is larger than the sum of its proper divisors (9154282).

18209138 is a wasteful number, since it uses less digits than its factorization.

18209138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 16572.

The product of its (nonzero) digits is 3456, while the sum is 32.

The square root of 18209138 is about 4267.2166572603. The cubic root of 18209138 is about 263.0852273336.

The spelling of 18209138 in words is "eighteen million, two hundred nine thousand, one hundred thirty-eight".