664320671 has 4 divisors (see below), whose sum is σ = 759223632. Its totient is φ = 569417712.

The previous prime is 664320649. The next prime is 664320673. The reversal of 664320671 is 176023466.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-664320671 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (664320673) 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, 47451470 + ... + 47451483.

It is an arithmetic number, because the mean of its divisors is an integer number (189805908).

Almost surely, 2^664320671 is an apocalyptic number.

664320671 is a deficient number, since it is larger than the sum of its proper divisors (94902961).

664320671 is an equidigital number, since it uses as much as digits as its factorization.

664320671 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 94902960.

The product of its (nonzero) digits is 36288, while the sum is 35.

The square root of 664320671 is about 25774.4189265248. The cubic root of 664320671 is about 872.5545524083.

The spelling of 664320671 in words is "six hundred sixty-four million, three hundred twenty thousand, six hundred seventy-one".