18136238 has 4 divisors (see below), whose sum is σ = 27204360. Its totient is φ = 9068118.

The previous prime is 18136211. The next prime is 18136243. The reversal of 18136238 is 83263181.

It is a happy number.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 83263181 = 8369 ⋅9949.

It is a congruent number.

It is an unprimeable number.

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 as a sum of consecutive naturals, namely, 4534058 + ... + 4534061.

It is an arithmetic number, because the mean of its divisors is an integer number (6801090).

Almost surely, 2^18136238 is an apocalyptic number.

18136238 is a deficient number, since it is larger than the sum of its proper divisors (9068122).

18136238 is an equidigital number, since it uses as much as digits as its factorization.

18136238 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9068121.

The product of its digits is 6912, while the sum is 32.

The square root of 18136238 is about 4258.6662231267. Note that the first 3 decimals coincide. The cubic root of 18136238 is about 262.7336718983.

The spelling of 18136238 in words is "eighteen million, one hundred thirty-six thousand, two hundred thirty-eight".