688540 has 24 divisors (see below), whose sum is σ = 1461600. Its totient is φ = 272448.

The previous prime is 688531. The next prime is 688543. The reversal of 688540 is 45886.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (688543) by changing a digit.

688540 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 7 ways as a sum of consecutive naturals, for example, 3361 + ... + 3559.

It is an arithmetic number, because the mean of its divisors is an integer number (60900).

2⁶⁸⁸⁵⁴⁰ is an apocalyptic number.

It is an amenable number.

688540 is an abundant number, since it is smaller than the sum of its proper divisors (773060).

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

688540 is a wasteful number, since it uses less digits than its factorization.

688540 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 381 (or 379 counting only the distinct ones).

The product of its (nonzero) digits is 7680, while the sum is 31.

The square root of 688540 is about 829.7831041905. The cubic root of 688540 is about 88.3031897464.

The spelling of 688540 in words is "six hundred eighty-eight thousand, five hundred forty".