66328681 has 2 divisors, whose sum is σ = 66328682. Its totient is φ = 66328680.

The previous prime is 66328667. The next prime is 66328709. The reversal of 66328681 is 18682366.

66328681 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., 44622400 + 21706281 = 6680^2 + 4659^2 .

It is a cyclic number.

It is not a de Polignac number, because 66328681 - 2⁵ = 66328649 is a prime.

It is a super-2 number, since 2×66328681² = 8798987846399522, which contains 22 as substring.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (66328651) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33164340 + 33164341.

It is an arithmetic number, because the mean of its divisors is an integer number (33164341).

Almost surely, 2^66328681 is an apocalyptic number.

It is an amenable number.

66328681 is a deficient number, since it is larger than the sum of its proper divisors (1).

66328681 is an equidigital number, since it uses as much as digits as its factorization.

66328681 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 82944, while the sum is 40.

The square root of 66328681 is about 8144.2421992473. The cubic root of 66328681 is about 404.7937394066.

The spelling of 66328681 in words is "sixty-six million, three hundred twenty-eight thousand, six hundred eighty-one".