18989566 has 4 divisors (see below), whose sum is σ = 28484352. Its totient is φ = 9494782.

The previous prime is 18989543. The next prime is 18989567. The reversal of 18989566 is 66598981.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 66598981 = 839 ⋅79379.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18989567) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4747390 + ... + 4747393.

It is an arithmetic number, because the mean of its divisors is an integer number (7121088).

Almost surely, 2^18989566 is an apocalyptic number.

18989566 is a deficient number, since it is larger than the sum of its proper divisors (9494786).

18989566 is an equidigital number, since it uses as much as digits as its factorization.

18989566 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9494785.

The product of its digits is 933120, while the sum is 52.

The square root of 18989566 is about 4357.7019172954. The cubic root of 18989566 is about 266.7913101337.

The spelling of 18989566 in words is "eighteen million, nine hundred eighty-nine thousand, five hundred sixty-six".