686311728 has 80 divisors (see below), whose sum is σ = 1852548096. Its totient is φ = 218684160.

The previous prime is 686311727. The next prime is 686311781. The reversal of 686311728 is 827113686.

It is a hoax number, since the sum of its digits (42) coincides with the sum of the digits of its distinct prime factors.

It is a self number, because there is not a number n which added to its sum of digits gives 686311728.

It is not an unprimeable number, because it can be changed into a prime (686311721) by changing a digit.

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, 120726 + ... + 126282.

Almost surely, 2^686311728 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 686311728, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (926274048).

686311728 is an abundant number, since it is smaller than the sum of its proper divisors (1166236368).

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

686311728 is a wasteful number, since it uses less digits than its factorization.

686311728 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 5682 (or 5676 counting only the distinct ones).

The product of its digits is 96768, while the sum is 42.

The square root of 686311728 is about 26197.5519466991. The cubic root of 686311728 is about 882.0783040398.

The spelling of 686311728 in words is "six hundred eighty-six million, three hundred eleven thousand, seven hundred twenty-eight".