664541671 has 2 divisors, whose sum is σ = 664541672. Its totient is φ = 664541670.

The previous prime is 664541659. The next prime is 664541707. The reversal of 664541671 is 176145466.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 664541671 - 2⁹ = 664541159 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664541621) 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 as a sum of consecutive naturals, namely, 332270835 + 332270836.

It is an arithmetic number, because the mean of its divisors is an integer number (332270836).

Almost surely, 2^664541671 is an apocalyptic number.

664541671 is a deficient number, since it is larger than the sum of its proper divisors (1).

664541671 is an equidigital number, since it uses as much as digits as its factorization.

664541671 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 120960, while the sum is 40.

The square root of 664541671 is about 25778.7057665818. The cubic root of 664541671 is about 872.6512994488.

The spelling of 664541671 in words is "six hundred sixty-four million, five hundred forty-one thousand, six hundred seventy-one".