688404 has 12 divisors (see below), whose sum is σ = 1606304. Its totient is φ = 229464.

The previous prime is 688403. The next prime is 688411. The reversal of 688404 is 404886.

It is a tau number, because it is divible by the number of its divisors (12).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688403) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 28672 + ... + 28695.

2⁶⁸⁸⁴⁰⁴ is an apocalyptic number.

It is an amenable number.

688404 is an abundant number, since it is smaller than the sum of its proper divisors (917900).

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

688404 is a wasteful number, since it uses less digits than its factorization.

688404 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 57374 (or 57372 counting only the distinct ones).

The product of its (nonzero) digits is 6144, while the sum is 30.

The square root of 688404 is about 829.7011510176. The cubic root of 688404 is about 88.2973754995.

It can be divided in two parts, 6 and 88404, that added together give a triangular number (88410 = T₄₂₀).

The spelling of 688404 in words is "six hundred eighty-eight thousand, four hundred four".