28704 has 48 divisors (see below), whose sum is σ = 84672. Its totient is φ = 8448.

The previous prime is 28703. The next prime is 28711. The reversal of 28704 is 40782.

It is a happy number.

28704 is an esthetic number in base 15, because in such base its adjacent digits differ by 1.

It is a tau number, because it is divible by the number of its divisors (48).

It is an Ulam number.

It is a nialpdrome in base 9 and base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (28703) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 1237 + ... + 1259.

It is an arithmetic number, because the mean of its divisors is an integer number (1764).

2²⁸⁷⁰⁴ is an apocalyptic number.

28704 is a gapful number since it is divisible by the number (24) 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 28704, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (42336).

28704 is an abundant number, since it is smaller than the sum of its proper divisors (55968).

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

28704 is a wasteful number, since it uses less digits than its factorization.

28704 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 49 (or 41 counting only the distinct ones).

The product of its (nonzero) digits is 448, while the sum is 21.

The square root of 28704 is about 169.4225486764. The cubic root of 28704 is about 30.6182811861.

The spelling of 28704 in words is "twenty-eight thousand, seven hundred four".