643813672 has 32 divisors (see below), whose sum is σ = 1215583200. Its totient is φ = 319668544.

The previous prime is 643813669. The next prime is 643813697. The reversal of 643813672 is 276318346.

643813672 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

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, 1378383 + ... + 1378849.

It is an arithmetic number, because the mean of its divisors is an integer number (37986975).

Almost surely, 2^643813672 is an apocalyptic number.

It is an amenable number.

643813672 is a deficient number, since it is larger than the sum of its proper divisors (571769528).

643813672 is a wasteful number, since it uses less digits than its factorization.

643813672 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1305 (or 1301 counting only the distinct ones).

The product of its digits is 145152, while the sum is 40.

The square root of 643813672 is about 25373.4836394217. The cubic root of 643813672 is about 863.4822179123.

The spelling of 643813672 in words is "six hundred forty-three million, eight hundred thirteen thousand, six hundred seventy-two".