78666697 has 2 divisors, whose sum is σ = 78666698. Its totient is φ = 78666696.

The previous prime is 78666677. The next prime is 78666703. The reversal of 78666697 is 79666687.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 70492816 + 8173881 = 8396^2 + 2859^2 .

It is a cyclic number.

It is not a de Polignac number, because 78666697 - 2⁷ = 78666569 is a prime.

It is not a weakly prime, because it can be changed into another prime (78666677) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 39333348 + 39333349.

It is an arithmetic number, because the mean of its divisors is an integer number (39333349).

Almost surely, 2^78666697 is an apocalyptic number.

It is an amenable number.

78666697 is a deficient number, since it is larger than the sum of its proper divisors (1).

78666697 is an equidigital number, since it uses as much as digits as its factorization.

78666697 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 4572288, while the sum is 55.

The square root of 78666697 is about 8869.4248404279. The cubic root of 78666697 is about 428.4797532536.

The spelling of 78666697 in words is "seventy-eight million, six hundred sixty-six thousand, six hundred ninety-seven".