643688252 has 12 divisors (see below), whose sum is σ = 1126688136. Its totient is φ = 321777360.

The previous prime is 643688249. The next prime is 643688261. The reversal of 643688252 is 252886346.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 9602 + ... + 37142.

It is an arithmetic number, because the mean of its divisors is an integer number (93890678).

Almost surely, 2^643688252 is an apocalyptic number.

It is an amenable number.

643688252 is a deficient number, since it is larger than the sum of its proper divisors (482999884).

643688252 is a wasteful number, since it uses less digits than its factorization.

643688252 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33388 (or 33386 counting only the distinct ones).

The product of its digits is 552960, while the sum is 44.

The square root of 643688252 is about 25371.0120413041. The cubic root of 643688252 is about 863.4261432137.

The spelling of 643688252 in words is "six hundred forty-three million, six hundred eighty-eight thousand, two hundred fifty-two".