66666142409 has 2 divisors, whose sum is σ = 66666142410. Its totient is φ = 66666142408.

The previous prime is 66666142391. The next prime is 66666142451. The reversal of 66666142409 is 90424166666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 48101262400 + 18564880009 = 219320^2 + 136253^2 .

It is a cyclic number.

It is not a de Polignac number, because 66666142409 - 2²⁸ = 66397706953 is a prime.

It is not a weakly prime, because it can be changed into another prime (66666142709) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33333071204 + 33333071205.

It is an arithmetic number, because the mean of its divisors is an integer number (33333071205).

Almost surely, 2^66666142409 is an apocalyptic number.

It is an amenable number.

66666142409 is a deficient number, since it is larger than the sum of its proper divisors (1).

66666142409 is an equidigital number, since it uses as much as digits as its factorization.

66666142409 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 2239488, while the sum is 50.

The spelling of 66666142409 in words is "sixty-six billion, six hundred sixty-six million, one hundred forty-two thousand, four hundred nine".