728665 has 16 divisors (see below), whose sum is σ = 1013760. Its totient is φ = 492480.

The previous prime is 728659. The next prime is 728681. The reversal of 728665 is 566827.

It is not a de Polignac number, because 728665 - 2⁷ = 728537 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 728665.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 3720 + ... + 3910.

It is an arithmetic number, because the mean of its divisors is an integer number (63360).

2⁷²⁸⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

728665 is a deficient number, since it is larger than the sum of its proper divisors (285095).

728665 is a wasteful number, since it uses less digits than its factorization.

728665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 312.

The product of its digits is 20160, while the sum is 34.

The square root of 728665 is about 853.6187673663. The cubic root of 728665 is about 89.9862118795.

The spelling of 728665 in words is "seven hundred twenty-eight thousand, six hundred sixty-five".