66061256602721 has 2 divisors, whose sum is σ = 66061256602722. Its totient is φ = 66061256602720.

The previous prime is 66061256602703. The next prime is 66061256602753. The reversal of 66061256602721 is 12720665216066.

66061256602721 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53619665277025 + 12441591325696 = 7322545^2 + 3527264^2 .

It is a cyclic number.

It is not a de Polignac number, because 66061256602721 - 2¹⁸ = 66061256340577 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66061256602721.

It is not a weakly prime, because it can be changed into another prime (66061256602771) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33030628301360 + 33030628301361.

It is an arithmetic number, because the mean of its divisors is an integer number (33030628301361).

Almost surely, 2^{66061256602721} is an apocalyptic number.

It is an amenable number.

66061256602721 is a deficient number, since it is larger than the sum of its proper divisors (1).

66061256602721 is an equidigital number, since it uses as much as digits as its factorization.

66061256602721 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2177280, while the sum is 50.

The spelling of 66061256602721 in words is "sixty-six trillion, sixty-one billion, two hundred fifty-six million, six hundred two thousand, seven hundred twenty-one".