66156320323217 has 2 divisors, whose sum is σ = 66156320323218. Its totient is φ = 66156320323216.

The previous prime is 66156320323153. The next prime is 66156320323229. The reversal of 66156320323217 is 71232302365166.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 57124588402561 + 9031731920656 = 7558081^2 + 3005284^2 .

It is a cyclic number.

It is not a de Polignac number, because 66156320323217 - 2⁶ = 66156320323153 is a prime.

It is not a weakly prime, because it can be changed into another prime (66156320329217) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 33078160161608 + 33078160161609.

It is an arithmetic number, because the mean of its divisors is an integer number (33078160161609).

Almost surely, 2^{66156320323217} is an apocalyptic number.

It is an amenable number.

66156320323217 is a deficient number, since it is larger than the sum of its proper divisors (1).

66156320323217 is an equidigital number, since it uses as much as digits as its factorization.

66156320323217 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 1632960, while the sum is 47.

The spelling of 66156320323217 in words is "sixty-six trillion, one hundred fifty-six billion, three hundred twenty million, three hundred twenty-three thousand, two hundred seventeen".