18008138 has 4 divisors (see below), whose sum is σ = 27012210. Its totient is φ = 9004068.

The previous prime is 18008131. The next prime is 18008153. The reversal of 18008138 is 83180081.

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: 83180081 = 19 ⋅4377899.

It can be written as a sum of positive squares in only one way, i.e., 15737089 + 2271049 = 3967^2 + 1507^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 18008138.

It is not an unprimeable number, because it can be changed into a prime (18008131) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4502033 + ... + 4502036.

Almost surely, 2^18008138 is an apocalyptic number.

18008138 is a deficient number, since it is larger than the sum of its proper divisors (9004072).

18008138 is an equidigital number, since it uses as much as digits as its factorization.

18008138 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9004071.

The product of its (nonzero) digits is 1536, while the sum is 29.

The square root of 18008138 is about 4243.5996512395. The cubic root of 18008138 is about 262.1136290137.

The spelling of 18008138 in words is "eighteen million, eight thousand, one hundred thirty-eight".