28724 has 12 divisors (see below), whose sum is σ = 51744.
Its totient is φ = 13944.
The previous prime is 28723. The next prime is 28729. The reversal of 28724 is 42782.
It is a hoax number, since the sum of its digits (23) coincides with the sum of the digits of its distinct prime factors.
It is a self number, because there is not a number n which added to its sum of digits gives 28724.
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 3 ways as a sum of consecutive naturals, for example, 89 + ... + 255.
It is an arithmetic number, because the mean of its divisors is an integer number (4312).
228724 is an apocalyptic number.
It is an amenable number.
28724 is a deficient number, since it is larger than the sum of its proper divisors (23020).
28724 is a wasteful number, since it uses less digits than its factorization.
28724 is an evil number, because the sum of its binary digits is even.
The sum of its prime factors is 214 (or 212 counting only the distinct ones).
The product of its digits is 896, while the sum is 23.
The square root of 28724 is about 169.4815624190.
The cubic root of 28724 is about 30.6253908044.
The spelling of 28724 in words is "twenty-eight thousand, seven hundred twenty-four".