643805992 has 16 divisors (see below), whose sum is σ = 1213459200. Its totient is φ = 320216880.

The previous prime is 643805983. The next prime is 643806001. The reversal of 643805992 is 299508346.

It is an interprime number because it is at equal distance from previous prime (643805983) and next prime (643806001).

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, 209142 + ... + 212197.

It is an arithmetic number, because the mean of its divisors is an integer number (75841200).

Almost surely, 2^643805992 is an apocalyptic number.

It is an amenable number.

643805992 is a deficient number, since it is larger than the sum of its proper divisors (569653208).

643805992 is a wasteful number, since it uses less digits than its factorization.

643805992 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 421536 (or 421532 counting only the distinct ones).

The product of its (nonzero) digits is 466560, while the sum is 46.

The square root of 643805992 is about 25373.3322998774. The cubic root of 643805992 is about 863.4787844294.

The spelling of 643805992 in words is "six hundred forty-three million, eight hundred five thousand, nine hundred ninety-two".