728785 has 4 divisors (see below), whose sum is σ = 874548. Its totient is φ = 583024.

The previous prime is 728771. The next prime is 728809. The reversal of 728785 is 587827.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 506944 + 221841 = 712^2 + 471^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-728785 is a prime.

It is a super-2 number, since 2×728785² = 1062255152450, which contains 22 as substring.

It is a Duffinian 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 3 ways as a sum of consecutive naturals, for example, 72874 + ... + 72883.

It is an arithmetic number, because the mean of its divisors is an integer number (218637).

2⁷²⁸⁷⁸⁵ is an apocalyptic number.

It is an amenable number.

728785 is a deficient number, since it is larger than the sum of its proper divisors (145763).

728785 is a wasteful number, since it uses less digits than its factorization.

728785 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 145762.

The product of its digits is 31360, while the sum is 37.

The square root of 728785 is about 853.6890534615. The cubic root of 728785 is about 89.9911513934.

The spelling of 728785 in words is "seven hundred twenty-eight thousand, seven hundred eighty-five".