66610278857 has 2 divisors, whose sum is σ = 66610278858. Its totient is φ = 66610278856.

The previous prime is 66610278853. The next prime is 66610278887. The reversal of 66610278857 is 75887201666.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 53310653881 + 13299624976 = 230891^2 + 115324^2 .

It is a cyclic number.

It is not a de Polignac number, because 66610278857 - 2² = 66610278853 is a prime.

It is not a weakly prime, because it can be changed into another prime (66610278853) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33305139428 + 33305139429.

It is an arithmetic number, because the mean of its divisors is an integer number (33305139429).

Almost surely, 2^66610278857 is an apocalyptic number.

It is an amenable number.

66610278857 is a deficient number, since it is larger than the sum of its proper divisors (1).

66610278857 is an equidigital number, since it uses as much as digits as its factorization.

66610278857 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6773760, while the sum is 56.

The spelling of 66610278857 in words is "sixty-six billion, six hundred ten million, two hundred seventy-eight thousand, eight hundred fifty-seven".