866240660261 has 2 divisors, whose sum is σ = 866240660262. Its totient is φ = 866240660260.

The previous prime is 866240660213. The next prime is 866240660279. The reversal of 866240660261 is 162066042668.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 571520880100 + 294719780161 = 755990^2 + 542881^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-866240660261 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (866240960261) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433120330130 + 433120330131.

It is an arithmetic number, because the mean of its divisors is an integer number (433120330131).

Almost surely, 2^866240660261 is an apocalyptic number.

It is an amenable number.

866240660261 is a deficient number, since it is larger than the sum of its proper divisors (1).

866240660261 is an equidigital number, since it uses as much as digits as its factorization.

866240660261 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 995328, while the sum is 47.

The spelling of 866240660261 in words is "eight hundred sixty-six billion, two hundred forty million, six hundred sixty thousand, two hundred sixty-one".