664051688 has 16 divisors (see below), whose sum is σ = 1318338180. Its totient is φ = 312494848.

The previous prime is 664051679. The next prime is 664051697. The reversal of 664051688 is 886150466.

It is an interprime number because it is at equal distance from previous prime (664051679) and next prime (664051697).

It can be written as a sum of positive squares in 2 ways, for example, as 544848964 + 119202724 = 23342^2 + 10918^2 .

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, 2441231 + ... + 2441502.

Almost surely, 2^664051688 is an apocalyptic number.

664051688 is a gapful number since it is divisible by the number (68) formed by its first and last digit.

It is an amenable number.

664051688 is a deficient number, since it is larger than the sum of its proper divisors (654286492).

664051688 is a wasteful number, since it uses less digits than its factorization.

664051688 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4882756 (or 4882752 counting only the distinct ones).

The product of its (nonzero) digits is 276480, while the sum is 44.

The square root of 664051688 is about 25769.2003756422. The cubic root of 664051688 is about 872.4367709234.

The spelling of 664051688 in words is "six hundred sixty-four million, fifty-one thousand, six hundred eighty-eight".