18538189 has 2 divisors, whose sum is σ = 18538190. Its totient is φ = 18538188.

The previous prime is 18538187. The next prime is 18538199. The reversal of 18538189 is 98183581.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 16892100 + 1646089 = 4110^2 + 1283^2 .

It is a cyclic number.

It is not a de Polignac number, because 18538189 - 2¹ = 18538187 is a prime.

Together with 18538187, it forms a pair of twin primes.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (18538183) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 9269094 + 9269095.

It is an arithmetic number, because the mean of its divisors is an integer number (9269095).

Almost surely, 2^18538189 is an apocalyptic number.

It is an amenable number.

18538189 is a deficient number, since it is larger than the sum of its proper divisors (1).

18538189 is an equidigital number, since it uses as much as digits as its factorization.

18538189 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 69120, while the sum is 43.

The square root of 18538189 is about 4305.5997259383. The cubic root of 18538189 is about 264.6604836759.

The spelling of 18538189 in words is "eighteen million, five hundred thirty-eight thousand, one hundred eighty-nine".