18138889 has 4 divisors (see below), whose sum is σ = 18219024. Its totient is φ = 18058756.

The previous prime is 18138871. The next prime is 18138919. The reversal of 18138889 is 98883181.

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 a cyclic number.

It is not a de Polignac number, because 18138889 - 2¹⁷ = 18007817 is a prime.

It is a super-3 number, since 3×18138889³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (18138829) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 39727 + ... + 40180.

It is an arithmetic number, because the mean of its divisors is an integer number (4554756).

Almost surely, 2^18138889 is an apocalyptic number.

It is an amenable number.

18138889 is a deficient number, since it is larger than the sum of its proper divisors (80135).

18138889 is an equidigital number, since it uses as much as digits as its factorization.

18138889 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 80134.

The product of its digits is 110592, while the sum is 46.

The square root of 18138889 is about 4258.9774594379. The cubic root of 18138889 is about 262.7464726609.

The spelling of 18138889 in words is "eighteen million, one hundred thirty-eight thousand, eight hundred eighty-nine".