643504020 has 48 divisors (see below), whose sum is σ = 1845764928. Its totient is φ = 167415040.

The previous prime is 643504013. The next prime is 643504079. The reversal of 643504020 is 20405346.

643504020 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, 128334 + ... + 133253.

It is an arithmetic number, because the mean of its divisors is an integer number (38453436).

Almost surely, 2^643504020 is an apocalyptic number.

643504020 is a gapful number since it is divisible by the number (60) formed by its first and last digit.

It is an amenable number.

643504020 is an abundant number, since it is smaller than the sum of its proper divisors (1202260908).

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

643504020 is a wasteful number, since it uses less digits than its factorization.

643504020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 261640 (or 261638 counting only the distinct ones).

The product of its (nonzero) digits is 2880, while the sum is 24.

The square root of 643504020 is about 25367.3810236690. The cubic root of 643504020 is about 863.3437607336.

Adding to 643504020 its reverse (20405346), we get a palindrome (663909366).

The spelling of 643504020 in words is "six hundred forty-three million, five hundred four thousand, twenty".