643316928 has 112 divisors (see below), whose sum is σ = 1763536224. Its totient is φ = 206807040.

The previous prime is 643316917. The next prime is 643316951. The reversal of 643316928 is 829613346.

It is a self number, because there is not a number n which added to its sum of digits gives 643316928.

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, 972918 + ... + 973578.

Almost surely, 2^643316928 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 643316928, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (881768112).

643316928 is an abundant number, since it is smaller than the sum of its proper divisors (1120219296).

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

643316928 is a wasteful number, since it uses less digits than its factorization.

643316928 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 850 (or 840 counting only the distinct ones).

The product of its digits is 186624, while the sum is 42.

The square root of 643316928 is about 25363.6931064859. The cubic root of 643316928 is about 863.2600832625.

The spelling of 643316928 in words is "six hundred forty-three million, three hundred sixteen thousand, nine hundred twenty-eight".