643925564 has 12 divisors (see below), whose sum is σ = 1127047488. Its totient is φ = 321912000.

The previous prime is 643925563. The next prime is 643925573. The reversal of 643925564 is 465529346.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643925563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 42389 + ... + 55539.

It is an arithmetic number, because the mean of its divisors is an integer number (93920624).

Almost surely, 2^643925564 is an apocalyptic number.

It is an amenable number.

643925564 is a deficient number, since it is larger than the sum of its proper divisors (483121924).

643925564 is a wasteful number, since it uses less digits than its factorization.

643925564 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25396 (or 25394 counting only the distinct ones).

The product of its digits is 777600, while the sum is 44.

The square root of 643925564 is about 25375.6884438630. The cubic root of 643925564 is about 863.5322381588.

The spelling of 643925564 in words is "six hundred forty-three million, nine hundred twenty-five thousand, five hundred sixty-four".