688400 has 30 divisors (see below), whose sum is σ = 1654842. Its totient is φ = 275200.

The previous prime is 688397. The next prime is 688403. The reversal of 688400 is 4886.

It is an interprime number because it is at equal distance from previous prime (688397) and next prime (688403).

It can be written as a sum of positive squares in 3 ways, for example, as 92416 + 595984 = 304^2 + 772^2 .

It is an Ulam number.

It is a nialpdrome in base 16.

It is a self number, because there is not a number n which added to its sum of digits gives 688400.

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

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 461 + ... + 1260.

2⁶⁸⁸⁴⁰⁰ is an apocalyptic number.

It is an amenable number.

688400 is an abundant number, since it is smaller than the sum of its proper divisors (966442).

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

688400 is a wasteful number, since it uses less digits than its factorization.

688400 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1739 (or 1728 counting only the distinct ones).

The product of its (nonzero) digits is 1536, while the sum is 26.

The square root of 688400 is about 829.6987405077. The cubic root of 688400 is about 88.2972044807.

The spelling of 688400 in words is "six hundred eighty-eight thousand, four hundred".