684664 has 24 divisors (see below), whose sum is σ = 1361880. Its totient is φ = 322080.

The previous prime is 684647. The next prime is 684683. The reversal of 684664 is 466486.

684664 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

684664 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 5 ways as a sum of consecutive naturals, for example, 11194 + ... + 11254.

It is an arithmetic number, because the mean of its divisors is an integer number (56745).

2⁶⁸⁴⁶⁶⁴ is an apocalyptic number.

It is an amenable number.

684664 is a deficient number, since it is larger than the sum of its proper divisors (677216).

684664 is a wasteful number, since it uses less digits than its factorization.

684664 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 151 (or 86 counting only the distinct ones).

The product of its digits is 27648, while the sum is 34.

The square root of 684664 is about 827.4442579413. Note that the first 3 decimals coincide. The cubic root of 684664 is about 88.1371827297.

The spelling of 684664 in words is "six hundred eighty-four thousand, six hundred sixty-four".