66681339941 has 2 divisors, whose sum is σ = 66681339942. Its totient is φ = 66681339940.

The previous prime is 66681339931. The next prime is 66681339961. The reversal of 66681339941 is 14993318666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 66597544225 + 83795716 = 258065^2 + 9154^2 .

It is a cyclic number.

It is not a de Polignac number, because 66681339941 - 2¹⁴ = 66681323557 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66681339931) 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, 33340669970 + 33340669971.

It is an arithmetic number, because the mean of its divisors is an integer number (33340669971).

Almost surely, 2^66681339941 is an apocalyptic number.

It is an amenable number.

66681339941 is a deficient number, since it is larger than the sum of its proper divisors (1).

66681339941 is an equidigital number, since it uses as much as digits as its factorization.

66681339941 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 5038848, while the sum is 56.

The spelling of 66681339941 in words is "sixty-six billion, six hundred eighty-one million, three hundred thirty-nine thousand, nine hundred forty-one".