643204820 has 54 divisors (see below), whose sum is σ = 1389683022. Its totient is φ = 250068416.

The previous prime is 643204813. The next prime is 643204829. The reversal of 643204820 is 28402346.

It can be written as a sum of positive squares in 3 ways, for example, as 176039824 + 467164996 = 13268^2 + 21614^2 .

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643204829) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 6011207 + ... + 6011313.

Almost surely, 2^643204820 is an apocalyptic number.

It is an amenable number.

643204820 is an abundant number, since it is smaller than the sum of its proper divisors (746478202).

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

643204820 is a wasteful number, since it uses less digits than its factorization.

643204820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 329 (or 167 counting only the distinct ones).

The product of its (nonzero) digits is 9216, while the sum is 29.

The square root of 643204820 is about 25361.4830008026. The cubic root of 643204820 is about 863.2099348418.

The spelling of 643204820 in words is "six hundred forty-three million, two hundred four thousand, eight hundred twenty".