728645 has 8 divisors (see below), whose sum is σ = 889080. Its totient is φ = 573120.

The previous prime is 728639. The next prime is 728647. The reversal of 728645 is 546827.

728645 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 4 ways, for example, as 11236 + 717409 = 106^2 + 847^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 728645 - 2¹⁰ = 727621 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (728647) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 890 + ... + 1499.

It is an arithmetic number, because the mean of its divisors is an integer number (111135).

2⁷²⁸⁶⁴⁵ is an apocalyptic number.

It is an amenable number.

728645 is a deficient number, since it is larger than the sum of its proper divisors (160435).

728645 is a wasteful number, since it uses less digits than its factorization.

728645 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2455.

The product of its digits is 13440, while the sum is 32.

The square root of 728645 is about 853.6070524545. The cubic root of 728645 is about 89.9853885745.

The spelling of 728645 in words is "seven hundred twenty-eight thousand, six hundred forty-five".