66688822778779 has 2 divisors, whose sum is σ = 66688822778780. Its totient is φ = 66688822778778.

The previous prime is 66688822778761. The next prime is 66688822778827. The reversal of 66688822778779 is 97787722888666.

It is a happy number.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 66688822778779 - 2³³ = 66680232844187 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 66688822778693 and 66688822778702.

It is not a weakly prime, because it can be changed into another prime (66688822778759) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33344411389389 + 33344411389390.

It is an arithmetic number, because the mean of its divisors is an integer number (33344411389390).

Almost surely, 2^{66688822778779} is an apocalyptic number.

66688822778779 is a deficient number, since it is larger than the sum of its proper divisors (1).

66688822778779 is an equidigital number, since it uses as much as digits as its factorization.

66688822778779 is an evil number, because the sum of its binary digits is even.

The product of its digits is 76473040896, while the sum is 91.

The spelling of 66688822778779 in words is "sixty-six trillion, six hundred eighty-eight billion, eight hundred twenty-two million, seven hundred seventy-eight thousand, seven hundred seventy-nine".