866786383716221 has 2 divisors, whose sum is σ = 866786383716222. Its totient is φ = 866786383716220.

The previous prime is 866786383716217. The next prime is 866786383716241. The reversal of 866786383716221 is 122617383687668.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 623730145668100 + 243056238048121 = 24974590^2 + 15590261^2 .

It is a cyclic number.

It is not a de Polignac number, because 866786383716221 - 2² = 866786383716217 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866786383716241) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433393191858110 + 433393191858111.

It is an arithmetic number, because the mean of its divisors is an integer number (433393191858111).

Almost surely, 2^{866786383716221} is an apocalyptic number.

It is an amenable number.

866786383716221 is a deficient number, since it is larger than the sum of its proper divisors (1).

866786383716221 is an equidigital number, since it uses as much as digits as its factorization.

866786383716221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 1170505728, while the sum is 74.

The spelling of 866786383716221 in words is "eight hundred sixty-six trillion, seven hundred eighty-six billion, three hundred eighty-three million, seven hundred sixteen thousand, two hundred twenty-one".