66766520501 has 2 divisors, whose sum is σ = 66766520502. Its totient is φ = 66766520500.

The previous prime is 66766520407. The next prime is 66766520539. The reversal of 66766520501 is 10502566766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 34249054225 + 32517466276 = 185065^2 + 180326^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66766520501 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66766520551) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33383260250 + 33383260251.

It is an arithmetic number, because the mean of its divisors is an integer number (33383260251).

Almost surely, 2^66766520501 is an apocalyptic number.

It is an amenable number.

66766520501 is a deficient number, since it is larger than the sum of its proper divisors (1).

66766520501 is an equidigital number, since it uses as much as digits as its factorization.

66766520501 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 453600, while the sum is 44.

The spelling of 66766520501 in words is "sixty-six billion, seven hundred sixty-six million, five hundred twenty thousand, five hundred one".