866802166064321 has 2 divisors, whose sum is σ = 866802166064322. Its totient is φ = 866802166064320.

The previous prime is 866802166064293. The next prime is 866802166064353. The reversal of 866802166064321 is 123460661208668.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 486118713610000 + 380683452454321 = 22048100^2 + 19511111^2 .

It is a cyclic number.

It is not a de Polignac number, because 866802166064321 - 2⁴² = 862404119553217 is a prime.

It is not a weakly prime, because it can be changed into another prime (866802136064321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433401083032160 + 433401083032161.

It is an arithmetic number, because the mean of its divisors is an integer number (433401083032161).

Almost surely, 2^{866802166064321} is an apocalyptic number.

It is an amenable number.

866802166064321 is a deficient number, since it is larger than the sum of its proper divisors (1).

866802166064321 is an equidigital number, since it uses as much as digits as its factorization.

866802166064321 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 23887872, while the sum is 59.

The spelling of 866802166064321 in words is "eight hundred sixty-six trillion, eight hundred two billion, one hundred sixty-six million, sixty-four thousand, three hundred twenty-one".