643427661568 has 36 divisors (see below), whose sum is σ = 1290796015600. Its totient is φ = 320097153024.

The previous prime is 643427661553. The next prime is 643427661571. The reversal of 643427661568 is 865166724346.

643427661568 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 6264105 + ... + 6365992.

Almost surely, 2^643427661568 is an apocalyptic number.

It is an amenable number.

643427661568 is an abundant number, since it is smaller than the sum of its proper divisors (647368354032).

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

643427661568 is a wasteful number, since it uses less digits than its factorization.

643427661568 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12630312 (or 12630298 counting only the distinct ones).

The product of its digits is 34836480, while the sum is 58.

The spelling of 643427661568 in words is "six hundred forty-three billion, four hundred twenty-seven million, six hundred sixty-one thousand, five hundred sixty-eight".