643910688 has 96 divisors (see below), whose sum is σ = 1884798720. Its totient is φ = 213868800.

The previous prime is 643910677. The next prime is 643910731. The reversal of 643910688 is 886019346.

It is a tau number, because it is divible by the number of its divisors (96).

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 272713 + ... + 275063.

It is an arithmetic number, because the mean of its divisors is an integer number (19633320).

Almost surely, 2^643910688 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 643910688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (942399360).

643910688 is an abundant number, since it is smaller than the sum of its proper divisors (1240888032).

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

643910688 is a wasteful number, since it uses less digits than its factorization.

643910688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2687 (or 2673 counting only the distinct ones).

The product of its (nonzero) digits is 248832, while the sum is 45.

The square root of 643910688 is about 25375.3953269698. The cubic root of 643910688 is about 863.5255883195.

The spelling of 643910688 in words is "six hundred forty-three million, nine hundred ten thousand, six hundred eighty-eight".