643666670 has 8 divisors (see below), whose sum is σ = 1158600024. Its totient is φ = 257466664.

The previous prime is 643666669. The next prime is 643666679. The reversal of 643666670 is 76666346.

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 (643666679) by changing a digit.

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, 32183324 + ... + 32183343.

It is an arithmetic number, because the mean of its divisors is an integer number (144825003).

Almost surely, 2^643666670 is an apocalyptic number.

643666670 is a deficient number, since it is larger than the sum of its proper divisors (514933354).

643666670 is a wasteful number, since it uses less digits than its factorization.

643666670 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 64366674.

The product of its (nonzero) digits is 653184, while the sum is 44.

The square root of 643666670 is about 25370.5867098102. The cubic root of 643666670 is about 863.4164932673.

The spelling of 643666670 in words is "six hundred forty-three million, six hundred sixty-six thousand, six hundred seventy".