643923708 has 48 divisors (see below), whose sum is σ = 1527273216. Its totient is φ = 211115520.

The previous prime is 643923647. The next prime is 643923719. The reversal of 643923708 is 807329346.

It is a self number, because there is not a number n which added to its sum of digits gives 643923708.

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, 572835 + ... + 573957.

It is an arithmetic number, because the mean of its divisors is an integer number (31818192).

Almost surely, 2^643923708 is an apocalyptic number.

It is an amenable number.

643923708 is an abundant number, since it is smaller than the sum of its proper divisors (883349508).

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

643923708 is a wasteful number, since it uses less digits than its factorization.

643923708 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1874 (or 1872 counting only the distinct ones).

The product of its (nonzero) digits is 217728, while the sum is 42.

The square root of 643923708 is about 25375.6518734002. The cubic root of 643923708 is about 863.5314084991.

The spelling of 643923708 in words is "six hundred forty-three million, nine hundred twenty-three thousand, seven hundred eight".