643574657 has 8 divisors (see below), whose sum is σ = 706795200. Its totient is φ = 581139760.

The previous prime is 643574653. The next prime is 643574677. The reversal of 643574657 is 756475346.

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

It is a cyclic number.

It is not a de Polignac number, because 643574657 - 2² = 643574653 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (643574653) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 194693 + ... + 197970.

It is an arithmetic number, because the mean of its divisors is an integer number (88349400).

Almost surely, 2^643574657 is an apocalyptic number.

It is an amenable number.

643574657 is a deficient number, since it is larger than the sum of its proper divisors (63220543).

643574657 is a wasteful number, since it uses less digits than its factorization.

643574657 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 392823.

The product of its digits is 2116800, while the sum is 47.

The square root of 643574657 is about 25368.7732655720. The cubic root of 643574657 is about 863.3753491310.

The spelling of 643574657 in words is "six hundred forty-three million, five hundred seventy-four thousand, six hundred fifty-seven".