257728 has 14 divisors (see below), whose sum is σ = 511556. Its totient is φ = 128832.

The previous prime is 257717. The next prime is 257731. The reversal of 257728 is 827752.

It is an Ulam number.

It is a self number, because there is not a number n which added to its sum of digits gives 257728.

It is an unprimeable number.

257728 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, 1950 + ... + 2077.

2²⁵⁷⁷²⁸ is an apocalyptic number.

It is an amenable number.

257728 is a deficient number, since it is larger than the sum of its proper divisors (253828).

257728 is an equidigital number, since it uses as much as digits as its factorization.

257728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4039 (or 4029 counting only the distinct ones).

The product of its digits is 7840, while the sum is 31.

The square root of 257728 is about 507.6691836226. The cubic root of 257728 is about 63.6385879247.

The spelling of 257728 in words is "two hundred fifty-seven thousand, seven hundred twenty-eight".