66558223709 has 2 divisors, whose sum is σ = 66558223710. Its totient is φ = 66558223708.

The previous prime is 66558223703. The next prime is 66558223717. The reversal of 66558223709 is 90732285566.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 59135539684 + 7422684025 = 243178^2 + 86155^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66558223709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66558223703) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33279111854 + 33279111855.

It is an arithmetic number, because the mean of its divisors is an integer number (33279111855).

Almost surely, 2^66558223709 is an apocalyptic number.

It is an amenable number.

66558223709 is a deficient number, since it is larger than the sum of its proper divisors (1).

66558223709 is an equidigital number, since it uses as much as digits as its factorization.

66558223709 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 5443200, while the sum is 53.

The spelling of 66558223709 in words is "sixty-six billion, five hundred fifty-eight million, two hundred twenty-three thousand, seven hundred nine".