643763320 has 64 divisors (see below), whose sum is σ = 1560240000. Its totient is φ = 238267008.

The previous prime is 643763299. The next prime is 643763347. The reversal of 643763320 is 23367346.

643763320 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a congruent number.

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, 22831 + ... + 42529.

It is an arithmetic number, because the mean of its divisors is an integer number (24378750).

Almost surely, 2^643763320 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 643763320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (780120000).

643763320 is an abundant number, since it is smaller than the sum of its proper divisors (916476680).

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

643763320 is a wasteful number, since it uses less digits than its factorization.

643763320 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19772 (or 19768 counting only the distinct ones).

The product of its (nonzero) digits is 54432, while the sum is 34.

The square root of 643763320 is about 25372.4914030924. The cubic root of 643763320 is about 863.4597066424.

The spelling of 643763320 in words is "six hundred forty-three million, seven hundred sixty-three thousand, three hundred twenty".