687928 has 8 divisors (see below), whose sum is σ = 1289880. Its totient is φ = 343960.

The previous prime is 687923. The next prime is 687931. The reversal of 687928 is 829786.

It is a tau number, because it is divible by the number of its divisors (8).

It is an Ulam number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (687923) by changing a digit.

687928 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 as a sum of consecutive naturals, namely, 42988 + ... + 43003.

It is an arithmetic number, because the mean of its divisors is an integer number (161235).

2⁶⁸⁷⁹²⁸ is an apocalyptic number.

It is an amenable number.

687928 is a deficient number, since it is larger than the sum of its proper divisors (601952).

687928 is a wasteful number, since it uses less digits than its factorization.

687928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 85997 (or 85993 counting only the distinct ones).

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

The square root of 687928 is about 829.4142511435. The cubic root of 687928 is about 88.2770196031.

The spelling of 687928 in words is "six hundred eighty-seven thousand, nine hundred twenty-eight".