643868684836 has 24 divisors (see below), whose sum is σ = 1213589378624. Its totient is φ = 297134762400.

The previous prime is 643868684827. The next prime is 643868684867. The reversal of 643868684836 is 638486868346.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 294240 + ... + 1172311.

Almost surely, 2^643868684836 is an apocalyptic number.

It is an amenable number.

643868684836 is a deficient number, since it is larger than the sum of its proper divisors (569720693788).

643868684836 is a wasteful number, since it uses less digits than its factorization.

643868684836 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1475011 (or 1475009 counting only the distinct ones).

The product of its digits is 764411904, while the sum is 70.

The spelling of 643868684836 in words is "six hundred forty-three billion, eight hundred sixty-eight million, six hundred eighty-four thousand, eight hundred thirty-six".