18720189 has 6 divisors (see below), whose sum is σ = 27040286. Its totient is φ = 12480120.

The previous prime is 18720173. The next prime is 18720197. The reversal of 18720189 is 98102781.

It can be written as a sum of positive squares in only one way, i.e., 15327225 + 3392964 = 3915^2 + 1842^2 .

It is not a de Polignac number, because 18720189 - 2⁴ = 18720173 is a prime.

It is a super-3 number, since 3×18720189³ (a number of 23 digits) contains 333 as substring.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18720389) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 1040002 + ... + 1040019.

Almost surely, 2^18720189 is an apocalyptic number.

It is an amenable number.

18720189 is a deficient number, since it is larger than the sum of its proper divisors (8320097).

18720189 is a wasteful number, since it uses less digits than its factorization.

18720189 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2080027 (or 2080024 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 18720189 is about 4326.6833718219. The cubic root of 18720189 is about 265.5237724360.

The spelling of 18720189 in words is "eighteen million, seven hundred twenty thousand, one hundred eighty-nine".