664817666173 has 2 divisors, whose sum is σ = 664817666174. Its totient is φ = 664817666172.

The previous prime is 664817666131. The next prime is 664817666179. The reversal of 664817666173 is 371666718466.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 341554918329 + 323262747844 = 584427^2 + 568562^2 .

It is a cyclic number.

It is not a de Polignac number, because 664817666173 - 2³³ = 656227731581 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (664817666179) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 332408833086 + 332408833087.

It is an arithmetic number, because the mean of its divisors is an integer number (332408833087).

Almost surely, 2^664817666173 is an apocalyptic number.

It is an amenable number.

664817666173 is a deficient number, since it is larger than the sum of its proper divisors (1).

664817666173 is an equidigital number, since it uses as much as digits as its factorization.

664817666173 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 36578304, while the sum is 61.

The spelling of 664817666173 in words is "six hundred sixty-four billion, eight hundred seventeen million, six hundred sixty-six thousand, one hundred seventy-three".