664505173 has 2 divisors, whose sum is σ = 664505174. Its totient is φ = 664505172.

The previous prime is 664505143. The next prime is 664505209. The reversal of 664505173 is 371505466.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 620109604 + 44395569 = 24902^2 + 6663^2 .

It is a cyclic number.

It is not a de Polignac number, because 664505173 - 2¹⁷ = 664374101 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664505113) 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, 332252586 + 332252587.

It is an arithmetic number, because the mean of its divisors is an integer number (332252587).

Almost surely, 2^664505173 is an apocalyptic number.

It is an amenable number.

664505173 is a deficient number, since it is larger than the sum of its proper divisors (1).

664505173 is an equidigital number, since it uses as much as digits as its factorization.

664505173 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 75600, while the sum is 37.

The square root of 664505173 is about 25777.9978470012. The cubic root of 664505173 is about 872.6353232195.

The spelling of 664505173 in words is "six hundred sixty-four million, five hundred five thousand, one hundred seventy-three".