688388646 has 16 divisors (see below), whose sum is σ = 1501939008. Its totient is φ = 208602600.

The previous prime is 688388627. The next prime is 688388671. The reversal of 688388646 is 646883886.

688388646 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 5215000 + ... + 5215131.

It is an arithmetic number, because the mean of its divisors is an integer number (93871188).

Almost surely, 2^688388646 is an apocalyptic number.

688388646 is a gapful number since it is divisible by the number (66) formed by its first and last digit.

688388646 is an abundant number, since it is smaller than the sum of its proper divisors (813550362).

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

688388646 is a wasteful number, since it uses less digits than its factorization.

688388646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10430147.

The product of its digits is 10616832, while the sum is 57.

The square root of 688388646 is about 26237.1615461734. The cubic root of 688388646 is about 882.9671904005.

The spelling of 688388646 in words is "six hundred eighty-eight million, three hundred eighty-eight thousand, six hundred forty-six".