18109728 has 144 divisors (see below), whose sum is σ = 63475776. Its totient is φ = 4769280.

The previous prime is 18109727. The next prime is 18109733. The reversal of 18109728 is 82790181.

It is a tau number, because it is divible by the number of its divisors (144).

It is a Harshad number since it is a multiple of its sum of digits (36).

It is a junction number, because it is equal to n+sod(n) for n = 18109692 and 18109701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18109727) by changing a digit.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 25863 + ... + 26553.

It is an arithmetic number, because the mean of its divisors is an integer number (440804).

Almost surely, 2^18109728 is an apocalyptic number.

18109728 is a gapful number since it is divisible by the number (18) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 18109728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (31737888).

18109728 is an abundant number, since it is smaller than the sum of its proper divisors (45366048).

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

18109728 is a wasteful number, since it uses less digits than its factorization.

18109728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 727 (or 716 counting only the distinct ones).

The product of its (nonzero) digits is 8064, while the sum is 36.

The square root of 18109728 is about 4255.5526080640. The cubic root of 18109728 is about 262.6055956117.

It can be divided in two parts, 18 and 109728, that added together give a triangular number (109746 = T₄₆₈).

The spelling of 18109728 in words is "eighteen million, one hundred nine thousand, seven hundred twenty-eight".