6664643968 has 16 divisors (see below), whose sum is σ = 13277220660. Its totient is φ = 3332321920.

The previous prime is 6664643963. The next prime is 6664643969. The reversal of 6664643968 is 8693464666.

It is a tau number, because it is divible by the number of its divisors (16).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6664643963) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 26033638 + ... + 26033893.

Almost surely, 2^6664643968 is an apocalyptic number.

It is an amenable number.

6664643968 is a deficient number, since it is larger than the sum of its proper divisors (6612576692).

6664643968 is an equidigital number, since it uses as much as digits as its factorization.

6664643968 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52067545 (or 52067533 counting only the distinct ones).

The product of its digits is 26873856, while the sum is 58.

The square root of 6664643968 is about 81637.2707040112. The cubic root of 6664643968 is about 1881.8816952764.

The spelling of 6664643968 in words is "six billion, six hundred sixty-four million, six hundred forty-three thousand, nine hundred sixty-eight".