643823328 has 48 divisors (see below), whose sum is σ = 1731267216. Its totient is φ = 209372160.

The previous prime is 643823321. The next prime is 643823339. The reversal of 643823328 is 823328346.

It is a tau number, because it is divible by the number of its divisors (48).

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643823321) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 77851 + ... + 85722.

It is an arithmetic number, because the mean of its divisors is an integer number (36068067).

Almost surely, 2^643823328 is an apocalyptic number.

It is an amenable number.

643823328 is an abundant number, since it is smaller than the sum of its proper divisors (1087443888).

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

643823328 is a wasteful number, since it uses less digits than its factorization.

643823328 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 163627 (or 163619 counting only the distinct ones).

The product of its digits is 165888, while the sum is 39.

The square root of 643823328 is about 25373.6739160887. The cubic root of 643823328 is about 863.4865347631.

The spelling of 643823328 in words is "six hundred forty-three million, eight hundred twenty-three thousand, three hundred twenty-eight".