66728385673 has 2 divisors, whose sum is σ = 66728385674. Its totient is φ = 66728385672.

The previous prime is 66728385653. The next prime is 66728385677. The reversal of 66728385673 is 37658382766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63687083769 + 3041301904 = 252363^2 + 55148^2 .

It is a cyclic number.

It is not a de Polignac number, because 66728385673 - 2³³ = 58138451081 is a prime.

It is not a weakly prime, because it can be changed into another prime (66728385677) 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, 33364192836 + 33364192837.

It is an arithmetic number, because the mean of its divisors is an integer number (33364192837).

Almost surely, 2^66728385673 is an apocalyptic number.

It is an amenable number.

66728385673 is a deficient number, since it is larger than the sum of its proper divisors (1).

66728385673 is an equidigital number, since it uses as much as digits as its factorization.

66728385673 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 60963840, while the sum is 61.

The spelling of 66728385673 in words is "sixty-six billion, seven hundred twenty-eight million, three hundred eighty-five thousand, six hundred seventy-three".