66688207 has 2 divisors, whose sum is σ = 66688208. Its totient is φ = 66688206.

The previous prime is 66688177. The next prime is 66688211. The reversal of 66688207 is 70288666.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66688207 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66688217) 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, 33344103 + 33344104.

It is an arithmetic number, because the mean of its divisors is an integer number (33344104).

Almost surely, 2^66688207 is an apocalyptic number.

66688207 is a deficient number, since it is larger than the sum of its proper divisors (1).

66688207 is an equidigital number, since it uses as much as digits as its factorization.

66688207 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 193536, while the sum is 43.

The square root of 66688207 is about 8166.2847733838. The cubic root of 66688207 is about 405.5237992218.

The spelling of 66688207 in words is "sixty-six million, six hundred eighty-eight thousand, two hundred seven".