866786278452761 has 2 divisors, whose sum is σ = 866786278452762. Its totient is φ = 866786278452760.

The previous prime is 866786278452691. The next prime is 866786278452781. The reversal of 866786278452761 is 167254872687668.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 510537414255625 + 356248864197136 = 22595075^2 + 18874556^2 .

It is a cyclic number.

It is not a de Polignac number, because 866786278452761 - 2³⁰ = 866785204710937 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 866786278452761.

It is not a weakly prime, because it can be changed into another prime (866786278452781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433393139226380 + 433393139226381.

It is an arithmetic number, because the mean of its divisors is an integer number (433393139226381).

Almost surely, 2^{866786278452761} is an apocalyptic number.

It is an amenable number.

866786278452761 is a deficient number, since it is larger than the sum of its proper divisors (1).

866786278452761 is an equidigital number, since it uses as much as digits as its factorization.

866786278452761 is an evil number, because the sum of its binary digits is even.

The product of its digits is 18207866880, while the sum is 83.

The spelling of 866786278452761 in words is "eight hundred sixty-six trillion, seven hundred eighty-six billion, two hundred seventy-eight million, four hundred fifty-two thousand, seven hundred sixty-one".