728109 has 20 divisors (see below), whose sum is σ = 1110780. Its totient is φ = 475200.

The previous prime is 728087. The next prime is 728113. The reversal of 728109 is 901827.

728109 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It can be written as a sum of positive squares in 2 ways, for example, as 455625 + 272484 = 675^2 + 522^2 .

It is not a de Polignac number, because 728109 - 2⁷ = 727981 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (27).

It is a Curzon number.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 728109.

It is not an unprimeable number, because it can be changed into a prime (728129) by changing a digit.

It is a polite number, since it can be written in 19 ways as a sum of consecutive naturals, for example, 7159 + ... + 7259.

It is an arithmetic number, because the mean of its divisors is an integer number (55539).

2⁷²⁸¹⁰⁹ is an apocalyptic number.

It is an amenable number.

728109 is a deficient number, since it is larger than the sum of its proper divisors (382671).

728109 is a wasteful number, since it uses less digits than its factorization.

728109 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 202 (or 193 counting only the distinct ones).

The product of its (nonzero) digits is 1008, while the sum is 27.

The square root of 728109 is about 853.2930329025. The cubic root of 728109 is about 89.9633183849.

The spelling of 728109 in words is "seven hundred twenty-eight thousand, one hundred nine".