18666779 has 2 divisors, whose sum is σ = 18666780. Its totient is φ = 18666778.

The previous prime is 18666763. The next prime is 18666821. The reversal of 18666779 is 97766681.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 18666779 - 2⁴ = 18666763 is a prime.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (18666709) 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, 9333389 + 9333390.

It is an arithmetic number, because the mean of its divisors is an integer number (9333390).

Almost surely, 2^18666779 is an apocalyptic number.

18666779 is a deficient number, since it is larger than the sum of its proper divisors (1).

18666779 is an equidigital number, since it uses as much as digits as its factorization.

18666779 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 762048, while the sum is 50.

The square root of 18666779 is about 4320.5067989762. The cubic root of 18666779 is about 265.2710126453.

The spelling of 18666779 in words is "eighteen million, six hundred sixty-six thousand, seven hundred seventy-nine".