643680646 has 8 divisors (see below), whose sum is σ = 1103452560. Its totient is φ = 275863128.

The previous prime is 643680641. The next prime is 643680647. The reversal of 643680646 is 646086346.

643680646 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (643680641) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 22988581 + ... + 22988608.

It is an arithmetic number, because the mean of its divisors is an integer number (137931570).

Almost surely, 2^643680646 is an apocalyptic number.

643680646 is a deficient number, since it is larger than the sum of its proper divisors (459771914).

643680646 is a wasteful number, since it uses less digits than its factorization.

643680646 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 45977198.

The product of its (nonzero) digits is 497664, while the sum is 43.

The square root of 643680646 is about 25370.8621453824. The cubic root of 643680646 is about 863.4227423722.

The spelling of 643680646 in words is "six hundred forty-three million, six hundred eighty thousand, six hundred forty-six".