66978849097 has 2 divisors, whose sum is σ = 66978849098. Its totient is φ = 66978849096.

The previous prime is 66978849089. The next prime is 66978849109. The reversal of 66978849097 is 79094887966.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 56299900176 + 10678948921 = 237276^2 + 103339^2 .

It is a cyclic number.

It is not a de Polignac number, because 66978849097 - 2³ = 66978849089 is a prime.

It is not a weakly prime, because it can be changed into another prime (66978849017) 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, 33489424548 + 33489424549.

It is an arithmetic number, because the mean of its divisors is an integer number (33489424549).

Almost surely, 2^66978849097 is an apocalyptic number.

It is an amenable number.

66978849097 is a deficient number, since it is larger than the sum of its proper divisors (1).

66978849097 is an equidigital number, since it uses as much as digits as its factorization.

66978849097 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 329204736, while the sum is 73.

The spelling of 66978849097 in words is "sixty-six billion, nine hundred seventy-eight million, eight hundred forty-nine thousand, ninety-seven".