285728 has 12 divisors (see below), whose sum is σ = 562590. Its totient is φ = 142848.

The previous prime is 285721. The next prime is 285731. The reversal of 285728 is 827582.

It can be written as a sum of positive squares in only one way, i.e., 283024 + 2704 = 532^2 + 52^2 .

It is a Harshad number since it is a multiple of its sum of digits (32), and also a Moran number because the ratio is a prime number: 8929 = 285728 / (2 + 8 + 5 + 7 + 2 + 8).

It is an Ulam number.

It is a d-powerful number, because it can be written as 2¹¹ + 8 + 7⁵ + 5⁴ + 2¹⁸ + 8⁴ .

It is a junction number, because it is equal to n+sod(n) for n = 285694 and 285703.

It is not an unprimeable number, because it can be changed into a prime (285721) by changing a digit.

285728 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4433 + ... + 4496.

2²⁸⁵⁷²⁸ is an apocalyptic number.

It is an amenable number.

285728 is a deficient number, since it is larger than the sum of its proper divisors (276862).

285728 is an equidigital number, since it uses as much as digits as its factorization.

285728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 8939 (or 8931 counting only the distinct ones).

The product of its digits is 8960, while the sum is 32.

The square root of 285728 is about 534.5353122105. The cubic root of 285728 is about 65.8644293980.

The spelling of 285728 in words is "two hundred eighty-five thousand, seven hundred twenty-eight".