643183640 has 32 divisors (see below), whose sum is σ = 1578724560. Its totient is φ = 233884800.

The previous prime is 643183621. The next prime is 643183693. The reversal of 643183640 is 46381346.

It is a self number, because there is not a number n which added to its sum of digits gives 643183640.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 730451 + ... + 731330.

Almost surely, 2^643183640 is an apocalyptic number.

It is an amenable number.

643183640 is an abundant number, since it is smaller than the sum of its proper divisors (935540920).

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

643183640 is a wasteful number, since it uses less digits than its factorization.

643183640 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1461803 (or 1461799 counting only the distinct ones).

The product of its (nonzero) digits is 41472, while the sum is 35.

The square root of 643183640 is about 25361.0654350325. The cubic root of 643183640 is about 863.2004598988.

The spelling of 643183640 in words is "six hundred forty-three million, one hundred eighty-three thousand, six hundred forty".