643664374 has 8 divisors (see below), whose sum is σ = 967791168. Its totient is φ = 321067320.

The previous prime is 643664369. The next prime is 643664401. The reversal of 643664374 is 473466346.

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

It is a self number, because there is not a number n which added to its sum of digits gives 643664374.

It is a congruent number.

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 3 ways as a sum of consecutive naturals, for example, 381382 + ... + 383065.

It is an arithmetic number, because the mean of its divisors is an integer number (120973896).

Almost surely, 2^643664374 is an apocalyptic number.

643664374 is a deficient number, since it is larger than the sum of its proper divisors (324126794).

643664374 is a wasteful number, since it uses less digits than its factorization.

643664374 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 764870.

The product of its digits is 870912, while the sum is 43.

The square root of 643664374 is about 25370.5414605207. The cubic root of 643664374 is about 863.4154666456.

The spelling of 643664374 in words is "six hundred forty-three million, six hundred sixty-four thousand, three hundred seventy-four".