66688822778947 has 2 divisors, whose sum is σ = 66688822778948. Its totient is φ = 66688822778946.

The previous prime is 66688822778843. The next prime is 66688822778969. The reversal of 66688822778947 is 74987722888666.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-66688822778947 is a prime.

It is not a weakly prime, because it can be changed into another prime (66688822772947) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33344411389473 + 33344411389474.

It is an arithmetic number, because the mean of its divisors is an integer number (33344411389474).

Almost surely, 2^{66688822778947} is an apocalyptic number.

66688822778947 is a deficient number, since it is larger than the sum of its proper divisors (1).

66688822778947 is an equidigital number, since it uses as much as digits as its factorization.

66688822778947 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 43698880512, while the sum is 88.

The spelling of 66688822778947 in words is "sixty-six trillion, six hundred eighty-eight billion, eight hundred twenty-two million, seven hundred seventy-eight thousand, nine hundred forty-seven".