18936389 has 6 divisors (see below), whose sum is σ = 19168146. Its totient is φ = 18705600.

The previous prime is 18936373. The next prime is 18936403. The reversal of 18936389 is 98363981.

It can be written as a sum of positive squares in 3 ways, for example, as 1085764 + 17850625 = 1042^2 + 4225^2 .

It is not a de Polignac number, because 18936389 - 2⁴ = 18936373 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 (18936289) 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, 43517 + ... + 43949.

It is an arithmetic number, because the mean of its divisors is an integer number (3194691).

Almost surely, 2^18936389 is an apocalyptic number.

It is an amenable number.

18936389 is a deficient number, since it is larger than the sum of its proper divisors (231757).

18936389 is an frugal number, since it uses more digits than its factorization.

18936389 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 967 (or 534 counting only the distinct ones).

The product of its digits is 279936, while the sum is 47.

The square root of 18936389 is about 4351.5961439453. The cubic root of 18936389 is about 266.5420429829.

The spelling of 18936389 in words is "eighteen million, nine hundred thirty-six thousand, three hundred eighty-nine".