28728 has 64 divisors (see below), whose sum is σ = 96000. Its totient is φ = 7776.

The previous prime is 28723. The next prime is 28729. The reversal of 28728 is 82782.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a nude number because it is divisible by every one of its digits.

It is a zygodrome in base 2.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28723) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 1503 + ... + 1521.

It is an arithmetic number, because the mean of its divisors is an integer number (1500).

28728 is a Friedman number, since it can be written as (8+(8^2)^2)*7, using all its digits and the basic arithmetic operations.

2²⁸⁷²⁸ is an apocalyptic number.

28728 is a gapful number since it is divisible by the number (28) 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 28728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (48000).

28728 is an abundant number, since it is smaller than the sum of its proper divisors (67272).

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

28728 is a wasteful number, since it uses less digits than its factorization.

28728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 41 (or 31 counting only the distinct ones).

The product of its digits is 1792, while the sum is 27.

The square root of 28728 is about 169.4933627019. The cubic root of 28728 is about 30.6268123320.

The spelling of 28728 in words is "twenty-eight thousand, seven hundred twenty-eight".