643990488 has 16 divisors (see below), whose sum is σ = 1609976280. Its totient is φ = 214663488.

The previous prime is 643990483. The next prime is 643990517. The reversal of 643990488 is 884099346.

It is a happy number.

It is a self number, because there is not a number n which added to its sum of digits gives 643990488.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643990483) 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, 13416445 + ... + 13416492.

Almost surely, 2^643990488 is an apocalyptic number.

It is an amenable number.

643990488 is an abundant number, since it is smaller than the sum of its proper divisors (965985792).

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

643990488 is a wasteful number, since it uses less digits than its factorization.

643990488 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26832946 (or 26832942 counting only the distinct ones).

The product of its (nonzero) digits is 1492992, while the sum is 51.

The square root of 643990488 is about 25376.9676675524. The cubic root of 643990488 is about 863.5612591544.

The spelling of 643990488 in words is "six hundred forty-three million, nine hundred ninety thousand, four hundred eighty-eight".