643629820 has 24 divisors (see below), whose sum is σ = 1374534000. Its totient is φ = 253087872.

The previous prime is 643629817. The next prime is 643629841. The reversal of 643629820 is 28926346.

643629820 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 7 ways as a sum of consecutive naturals, for example, 271545 + ... + 273904.

It is an arithmetic number, because the mean of its divisors is an integer number (57272250).

Almost surely, 2^643629820 is an apocalyptic number.

It is an amenable number.

643629820 is an abundant number, since it is smaller than the sum of its proper divisors (730904180).

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

643629820 is a wasteful number, since it uses less digits than its factorization.

643629820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 545517 (or 545515 counting only the distinct ones).

The product of its (nonzero) digits is 124416, while the sum is 40.

The square root of 643629820 is about 25369.8604647326. The cubic root of 643629820 is about 863.4000160509.

The spelling of 643629820 in words is "six hundred forty-three million, six hundred twenty-nine thousand, eight hundred twenty".