66766916647 has 2 divisors, whose sum is σ = 66766916648. Its totient is φ = 66766916646.

The previous prime is 66766916641. The next prime is 66766916669. The reversal of 66766916647 is 74661966766.

It is a weak prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66766916647 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66766916641) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33383458323 + 33383458324.

It is an arithmetic number, because the mean of its divisors is an integer number (33383458324).

Almost surely, 2^66766916647 is an apocalyptic number.

66766916647 is a deficient number, since it is larger than the sum of its proper divisors (1).

66766916647 is an equidigital number, since it uses as much as digits as its factorization.

66766916647 is an evil number, because the sum of its binary digits is even.

The product of its digits is 82301184, while the sum is 64.

The spelling of 66766916647 in words is "sixty-six billion, seven hundred sixty-six million, nine hundred sixteen thousand, six hundred forty-seven".