18668728 has 32 divisors (see below), whose sum is σ = 38228400. Its totient is φ = 8494848.

The previous prime is 18668701. The next prime is 18668753. The reversal of 18668728 is 82786681.

It is a congruent number.

It is an unprimeable number.

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 in 7 ways as a sum of consecutive naturals, for example, 6363 + ... + 8821.

Almost surely, 2^18668728 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18668728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (19114200).

18668728 is an abundant number, since it is smaller than the sum of its proper divisors (19559672).

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

18668728 is a wasteful number, since it uses less digits than its factorization.

18668728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2551 (or 2547 counting only the distinct ones).

The product of its digits is 258048, while the sum is 46.

The square root of 18668728 is about 4320.7323453322. The cubic root of 18668728 is about 265.2802446471.

It can be divided in two parts, 18 and 668728, that added together give a triangular number (668746 = T₁₁₅₆).

The spelling of 18668728 in words is "eighteen million, six hundred sixty-eight thousand, seven hundred twenty-eight".