66780358205647 has 2 divisors, whose sum is σ = 66780358205648. Its totient is φ = 66780358205646.

The previous prime is 66780358205581. The next prime is 66780358205677. The reversal of 66780358205647 is 74650285308766.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 66780358205647 - 2²³ = 66780349817039 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (66780358205677) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33390179102823 + 33390179102824.

It is an arithmetic number, because the mean of its divisors is an integer number (33390179102824).

Almost surely, 2^{66780358205647} is an apocalyptic number.

66780358205647 is a deficient number, since it is larger than the sum of its proper divisors (1).

66780358205647 is an equidigital number, since it uses as much as digits as its factorization.

66780358205647 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 406425600, while the sum is 67.

The spelling of 66780358205647 in words is "sixty-six trillion, seven hundred eighty billion, three hundred fifty-eight million, two hundred five thousand, six hundred forty-seven".