666658693 has 2 divisors, whose sum is σ = 666658694. Its totient is φ = 666658692.

The previous prime is 666658679. The next prime is 666658709. The reversal of 666658693 is 396856666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 527253444 + 139405249 = 22962^2 + 11807^2 .

It is a cyclic number.

It is not a de Polignac number, because 666658693 - 2⁵ = 666658661 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (666658633) 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, 333329346 + 333329347.

It is an arithmetic number, because the mean of its divisors is an integer number (333329347).

Almost surely, 2^666658693 is an apocalyptic number.

It is an amenable number.

666658693 is a deficient number, since it is larger than the sum of its proper divisors (1).

666658693 is an equidigital number, since it uses as much as digits as its factorization.

666658693 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 8398080, while the sum is 55.

The square root of 666658693 is about 25819.7345648634. The cubic root of 666658693 is about 873.5769819027.

The spelling of 666658693 in words is "six hundred sixty-six million, six hundred fifty-eight thousand, six hundred ninety-three".