18138893 has 4 divisors (see below), whose sum is σ = 18318588. Its totient is φ = 17959200.

The previous prime is 18138871. The next prime is 18138919. The reversal of 18138893 is 39883181.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 12369289 + 5769604 = 3517^2 + 2402^2 .

It is a cyclic number.

It is not a de Polignac number, because 18138893 - 2⁶ = 18138829 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 18138893.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18138853) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 89696 + ... + 89897.

It is an arithmetic number, because the mean of its divisors is an integer number (4579647).

Almost surely, 2^18138893 is an apocalyptic number.

It is an amenable number.

18138893 is a deficient number, since it is larger than the sum of its proper divisors (179695).

18138893 is a wasteful number, since it uses less digits than its factorization.

18138893 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 179694.

The product of its digits is 41472, while the sum is 41.

The square root of 18138893 is about 4258.9779290341. The cubic root of 18138893 is about 262.7464919746.

The spelling of 18138893 in words is "eighteen million, one hundred thirty-eight thousand, eight hundred ninety-three".