688243840 has 64 divisors (see below), whose sum is σ = 1731960000. Its totient is φ = 260803584.

The previous prime is 688243819. The next prime is 688243847. The reversal of 688243840 is 48342886.

It is a tau number, because it is divible by the number of its divisors (64).

It is not an unprimeable number, because it can be changed into a prime (688243847) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 16140 + ... + 40459.

It is an arithmetic number, because the mean of its divisors is an integer number (27061875).

Almost surely, 2^688243840 is an apocalyptic number.

It is an amenable number.

688243840 is an abundant number, since it is smaller than the sum of its proper divisors (1043716160).

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

688243840 is a wasteful number, since it uses less digits than its factorization.

688243840 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 56637 (or 56625 counting only the distinct ones).

The product of its (nonzero) digits is 294912, while the sum is 43.

The square root of 688243840 is about 26234.4018418564. The cubic root of 688243840 is about 882.9052738683.

The spelling of 688243840 in words is "six hundred eighty-eight million, two hundred forty-three thousand, eight hundred forty".