66668888668777 has 2 divisors, whose sum is σ = 66668888668778. Its totient is φ = 66668888668776.

The previous prime is 66668888668631. The next prime is 66668888668787. The reversal of 66668888668777 is 77786688886666.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 51937332043536 + 14731556625241 = 7206756^2 + 3838171^2 .

It is a cyclic number.

It is not a de Polignac number, because 66668888668777 - 2³¹ = 66666741185129 is a prime.

It is not a weakly prime, because it can be changed into another prime (66668888668787) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33334444334388 + 33334444334389.

It is an arithmetic number, because the mean of its divisors is an integer number (33334444334389).

Almost surely, 2^{66668888668777} is an apocalyptic number.

It is an amenable number.

66668888668777 is a deficient number, since it is larger than the sum of its proper divisors (1).

66668888668777 is an equidigital number, since it uses as much as digits as its factorization.

66668888668777 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 524386566144, while the sum is 97.

The spelling of 66668888668777 in words is "sixty-six trillion, six hundred sixty-eight billion, eight hundred eighty-eight million, six hundred sixty-eight thousand, seven hundred seventy-seven".