643909408688 has 240 divisors, whose sum is σ = 1592835552000. Its totient is φ = 245549283840.

The previous prime is 643909408679. The next prime is 643909408699. The reversal of 643909408688 is 886804909346.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 429558563 + ... + 429560061.

It is an arithmetic number, because the mean of its divisors is an integer number (6636814800).

Almost surely, 2^643909408688 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 643909408688, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (796417776000).

643909408688 is an abundant number, since it is smaller than the sum of its proper divisors (948926143312).

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

643909408688 is a wasteful number, since it uses less digits than its factorization.

643909408688 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1896 (or 1859 counting only the distinct ones).

The product of its (nonzero) digits is 71663616, while the sum is 65.

The spelling of 643909408688 in words is "six hundred forty-three billion, nine hundred nine million, four hundred eight thousand, six hundred eighty-eight".