66728385797 has 2 divisors, whose sum is σ = 66728385798. Its totient is φ = 66728385796.

The previous prime is 66728385793. The next prime is 66728385859. The reversal of 66728385797 is 79758382766.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 61984069156 + 4744316641 = 248966^2 + 68879^2 .

It is a cyclic number.

It is not a de Polignac number, because 66728385797 - 2² = 66728385793 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66728385793) 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, 33364192898 + 33364192899.

It is an arithmetic number, because the mean of its divisors is an integer number (33364192899).

Almost surely, 2^66728385797 is an apocalyptic number.

It is an amenable number.

66728385797 is a deficient number, since it is larger than the sum of its proper divisors (1).

66728385797 is an equidigital number, since it uses as much as digits as its factorization.

66728385797 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 213373440, while the sum is 68.

The spelling of 66728385797 in words is "sixty-six billion, seven hundred twenty-eight million, three hundred eighty-five thousand, seven hundred ninety-seven".