509728 has 24 divisors (see below), whose sum is σ = 1063692. Its totient is φ = 239616.

The previous prime is 509723. The next prime is 509731. The reversal of 509728 is 827905.

It can be written as a sum of positive squares in 2 ways, for example, as 501264 + 8464 = 708^2 + 92^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 509728.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (509723) by changing a digit.

509728 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 in 3 ways as a sum of consecutive naturals, for example, 76 + ... + 1012.

2⁵⁰⁹⁷²⁸ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 509728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (531846).

509728 is an abundant number, since it is smaller than the sum of its proper divisors (553964).

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

509728 is a wasteful number, since it uses less digits than its factorization.

509728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 964 (or 956 counting only the distinct ones).

The product of its (nonzero) digits is 5040, while the sum is 31.

The square root of 509728 is about 713.9523793643. The cubic root of 509728 is about 79.8814911992.

The spelling of 509728 in words is "five hundred nine thousand, seven hundred twenty-eight".