688664726 has 12 divisors (see below), whose sum is σ = 1048877628. Its totient is φ = 339043452.

The previous prime is 688664707. The next prime is 688664759. The reversal of 688664726 is 627466886.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 302645 + ... + 304911.

It is an arithmetic number, because the mean of its divisors is an integer number (87406469).

Almost surely, 2^688664726 is an apocalyptic number.

688664726 is a deficient number, since it is larger than the sum of its proper divisors (360212902).

688664726 is an frugal number, since it uses more digits than its factorization.

688664726 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4603 (or 2336 counting only the distinct ones).

The product of its digits is 4644864, while the sum is 53.

The square root of 688664726 is about 26242.4222586254. The cubic root of 688664726 is about 883.0852133625.

The spelling of 688664726 in words is "six hundred eighty-eight million, six hundred sixty-four thousand, seven hundred twenty-six".