66993517 has 2 divisors, whose sum is σ = 66993518. Its totient is φ = 66993516.

The previous prime is 66993499. The next prime is 66993523. The reversal of 66993517 is 71539966.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 49928356 + 17065161 = 7066^2 + 4131^2 .

It is a cyclic number.

It is not a de Polignac number, because 66993517 - 2¹¹ = 66991469 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66993547) 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, 33496758 + 33496759.

It is an arithmetic number, because the mean of its divisors is an integer number (33496759).

Almost surely, 2^66993517 is an apocalyptic number.

It is an amenable number.

66993517 is a deficient number, since it is larger than the sum of its proper divisors (1).

66993517 is an equidigital number, since it uses as much as digits as its factorization.

66993517 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 306180, while the sum is 46.

The square root of 66993517 is about 8184.9567500385. The cubic root of 66993517 is about 406.1417096139.

The spelling of 66993517 in words is "sixty-six million, nine hundred ninety-three thousand, five hundred seventeen".