689728 has 28 divisors (see below), whose sum is σ = 1475740. Its totient is φ = 317952.

The previous prime is 689723. The next prime is 689761. The reversal of 689728 is 827986.

It can be written as a sum of positive squares in 2 ways, for example, as 238144 + 451584 = 488^2 + 672^2 .

It is a nialpdrome in base 16.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (689723) by changing a digit.

689728 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, 418 + ... + 1246.

It is an arithmetic number, because the mean of its divisors is an integer number (52705).

2⁶⁸⁹⁷²⁸ 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 689728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (737870).

689728 is an abundant number, since it is smaller than the sum of its proper divisors (786012).

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

689728 is a wasteful number, since it uses less digits than its factorization.

689728 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 854 (or 844 counting only the distinct ones).

The product of its digits is 48384, while the sum is 40.

The square root of 689728 is about 830.4986453932. The cubic root of 689728 is about 88.3539463781.

The spelling of 689728 in words is "six hundred eighty-nine thousand, seven hundred twenty-eight".