866536701756421 has 2 divisors, whose sum is σ = 866536701756422. Its totient is φ = 866536701756420.

The previous prime is 866536701756331. The next prime is 866536701756433. The reversal of 866536701756421 is 124657107635668.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 480178955436196 + 386357746320225 = 21912986^2 + 19655985^2 .

It is a cyclic number.

It is not a de Polignac number, because 866536701756421 - 2⁹ = 866536701755909 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866536701786421) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433268350878210 + 433268350878211.

It is an arithmetic number, because the mean of its divisors is an integer number (433268350878211).

Almost surely, 2^{866536701756421} is an apocalyptic number.

It is an amenable number.

866536701756421 is a deficient number, since it is larger than the sum of its proper divisors (1).

866536701756421 is an equidigital number, since it uses as much as digits as its factorization.

866536701756421 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 304819200, while the sum is 67.

The spelling of 866536701756421 in words is "eight hundred sixty-six trillion, five hundred thirty-six billion, seven hundred one million, seven hundred fifty-six thousand, four hundred twenty-one".