18861728 has 24 divisors (see below), whose sum is σ = 37231488. Its totient is φ = 9406144.

The previous prime is 18861727. The next prime is 18861743. The reversal of 18861728 is 82716881.

It is not an unprimeable number, because it can be changed into a prime (18861727) 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 in 3 ways as a sum of consecutive naturals, for example, 21425 + ... + 22287.

It is an arithmetic number, because the mean of its divisors is an integer number (1551312).

Almost surely, 2^18861728 is an apocalyptic number.

It is an amenable number.

18861728 is a deficient number, since it is larger than the sum of its proper divisors (18369760).

18861728 is an equidigital number, since it uses as much as digits as its factorization.

18861728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1556 (or 1548 counting only the distinct ones).

The product of its digits is 43008, while the sum is 41.

The square root of 18861728 is about 4343.0090950860. The cubic root of 18861728 is about 266.1912808125.

It can be divided in two parts, 188 and 61728, that added together give a palindrome (61916).

The spelling of 18861728 in words is "eighteen million, eight hundred sixty-one thousand, seven hundred twenty-eight".