643907884 has 6 divisors (see below), whose sum is σ = 1126838804. Its totient is φ = 321953940.

The previous prime is 643907881. The next prime is 643907921. The reversal of 643907884 is 488709346.

It is not an unprimeable number, because it can be changed into a prime (643907881) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 80488482 + ... + 80488489.

Almost surely, 2^643907884 is an apocalyptic number.

It is an amenable number.

643907884 is a deficient number, since it is larger than the sum of its proper divisors (482930920).

643907884 is a wasteful number, since it uses less digits than its factorization.

643907884 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 160976975 (or 160976973 counting only the distinct ones).

The product of its (nonzero) digits is 1161216, while the sum is 49.

The square root of 643907884 is about 25375.3400765389. The cubic root of 643907884 is about 863.5243348697.

The spelling of 643907884 in words is "six hundred forty-three million, nine hundred seven thousand, eight hundred eighty-four".