18331728 has 20 divisors (see below), whose sum is σ = 47357088. Its totient is φ = 6110560.

The previous prime is 18331727. The next prime is 18331769. The reversal of 18331728 is 82713381.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18331721) 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, 190908 + ... + 191003.

Almost surely, 2^18331728 is an apocalyptic number.

It is an amenable number.

18331728 is an abundant number, since it is smaller than the sum of its proper divisors (29025360).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

18331728 is a wasteful number, since it uses less digits than its factorization.

18331728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 381922 (or 381916 counting only the distinct ones).

The product of its digits is 8064, while the sum is 33.

The square root of 18331728 is about 4281.5567262387. The cubic root of 18331728 is about 263.6742999060.

The spelling of 18331728 in words is "eighteen million, three hundred thirty-one thousand, seven hundred twenty-eight".