664698688 has 28 divisors (see below), whose sum is σ = 1322384452. Its totient is φ = 331499520.

The previous prime is 664698649. The next prime is 664698701. The reversal of 664698688 is 886896466.

It can be written as a sum of positive squares in 2 ways, for example, as 302481664 + 362217024 = 17392^2 + 19032^2 .

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 12328 + ... + 38488.

Almost surely, 2^664698688 is an apocalyptic number.

It is an amenable number.

664698688 is a deficient number, since it is larger than the sum of its proper divisors (657685764).

664698688 is a wasteful number, since it uses less digits than its factorization.

664698688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26570 (or 26560 counting only the distinct ones).

The product of its digits is 23887872, while the sum is 61.

The square root of 664698688 is about 25781.7510654339. The cubic root of 664698688 is about 872.7200236561.

It can be divided in two parts, 66469 and 8688, that added together give a palindrome (75157).

The spelling of 664698688 in words is "six hundred sixty-four million, six hundred ninety-eight thousand, six hundred eighty-eight".