643885861584 has 160 divisors (see below), whose sum is σ = 1963304943616. Its totient is φ = 177943495680.

The previous prime is 643885861579. The next prime is 643885861607. The reversal of 643885861584 is 485168588346.

It is a congruent number.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 22244529 + ... + 22273455.

Almost surely, 2^643885861584 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 643885861584, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (981652471808).

643885861584 is an abundant number, since it is smaller than the sum of its proper divisors (1319419082032).

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

643885861584 is a wasteful number, since it uses less digits than its factorization.

643885861584 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 31113 (or 31107 counting only the distinct ones).

The product of its digits is 176947200, while the sum is 66.

The spelling of 643885861584 in words is "six hundred forty-three billion, eight hundred eighty-five million, eight hundred sixty-one thousand, five hundred eighty-four".