66766657 has 2 divisors, whose sum is σ = 66766658. Its totient is φ = 66766656.

The previous prime is 66766621. The next prime is 66766663. The reversal of 66766657 is 75666766.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 53231616 + 13535041 = 7296^2 + 3679^2 .

It is a cyclic number.

It is not a de Polignac number, because 66766657 - 2¹¹ = 66764609 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 66766657.

It is not a weakly prime, because it can be changed into another prime (66766957) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33383328 + 33383329.

It is an arithmetic number, because the mean of its divisors is an integer number (33383329).

Almost surely, 2^66766657 is an apocalyptic number.

It is an amenable number.

66766657 is a deficient number, since it is larger than the sum of its proper divisors (1).

66766657 is an equidigital number, since it uses as much as digits as its factorization.

66766657 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1905120, while the sum is 49.

The square root of 66766657 is about 8171.0866474417. The cubic root of 66766657 is about 405.6827522405.

The spelling of 66766657 in words is "sixty-six million, seven hundred sixty-six thousand, six hundred fifty-seven".