660666779 has 2 divisors, whose sum is σ = 660666780. Its totient is φ = 660666778.

The previous prime is 660666757. The next prime is 660666793. The reversal of 660666779 is 977666066.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 660666779 - 2¹² = 660662683 is a prime.

It is a Chen prime.

It is a self number, because there is not a number n which added to its sum of digits gives 660666779.

It is not a weakly prime, because it can be changed into another prime (660666379) 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, 330333389 + 330333390.

It is an arithmetic number, because the mean of its divisors is an integer number (330333390).

Almost surely, 2^660666779 is an apocalyptic number.

660666779 is a deficient number, since it is larger than the sum of its proper divisors (1).

660666779 is an equidigital number, since it uses as much as digits as its factorization.

660666779 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3429216, while the sum is 53.

The square root of 660666779 is about 25703.4390500571. The cubic root of 660666779 is about 870.9518709321.

The spelling of 660666779 in words is "six hundred sixty million, six hundred sixty-six thousand, seven hundred seventy-nine".