18685189 has 4 divisors (see below), whose sum is σ = 19668640. Its totient is φ = 17701740.

The previous prime is 18685187. The next prime is 18685213. The reversal of 18685189 is 98158681.

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, and also an emirpimes, since its reverse is a distinct semiprime: 98158681 = 127 ⋅772903.

It is a cyclic number.

It is not a de Polignac number, because 18685189 - 2¹ = 18685187 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18685181) 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, 491697 + ... + 491734.

It is an arithmetic number, because the mean of its divisors is an integer number (4917160).

Almost surely, 2^18685189 is an apocalyptic number.

18685189 is a gapful number since it is divisible by the number (19) formed by its first and last digit.

It is an amenable number.

18685189 is a deficient number, since it is larger than the sum of its proper divisors (983451).

18685189 is an equidigital number, since it uses as much as digits as its factorization.

18685189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 983450.

The product of its digits is 138240, while the sum is 46.

The square root of 18685189 is about 4322.6368110217. The cubic root of 18685189 is about 265.3581913124.

The spelling of 18685189 in words is "eighteen million, six hundred eighty-five thousand, one hundred eighty-nine".