643693872 has 40 divisors (see below), whose sum is σ = 1663844400. Its totient is φ = 214439680.

The previous prime is 643693867. The next prime is 643693901. The reversal of 643693872 is 278396346.

It is a Harshad number since it is a multiple of its sum of digits (48).

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 119722 + ... + 124982.

It is an arithmetic number, because the mean of its divisors is an integer number (41596110).

Almost surely, 2^643693872 is an apocalyptic number.

It is an amenable number.

643693872 is an abundant number, since it is smaller than the sum of its proper divisors (1020150528).

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

643693872 is a wasteful number, since it uses less digits than its factorization.

643693872 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7821 (or 7815 counting only the distinct ones).

The product of its digits is 1306368, while the sum is 48.

The square root of 643693872 is about 25371.1227973852. The cubic root of 643693872 is about 863.4286560454.

The spelling of 643693872 in words is "six hundred forty-three million, six hundred ninety-three thousand, eight hundred seventy-two".