18271728 has 60 divisors (see below), whose sum is σ = 51455040. Its totient is φ = 6052608.

The previous prime is 18271723. The next prime is 18271777. The reversal of 18271728 is 82717281.

It is a happy number.

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 = 18271692 and 18271701.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (18271723) 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 11 ways as a sum of consecutive naturals, for example, 31828 + ... + 32396.

It is an arithmetic number, because the mean of its divisors is an integer number (857584).

Almost surely, 2^18271728 is an apocalyptic number.

18271728 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 18271728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25727520).

18271728 is an abundant number, since it is smaller than the sum of its proper divisors (33183312).

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

18271728 is a wasteful number, since it uses less digits than its factorization.

18271728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 806 (or 797 counting only the distinct ones).

The product of its digits is 12544, while the sum is 36.

The square root of 18271728 is about 4274.5441862262. The cubic root of 18271728 is about 263.3863156047.

The spelling of 18271728 in words is "eighteen million, two hundred seventy-one thousand, seven hundred twenty-eight".