866511756605161 has 2 divisors, whose sum is σ = 866511756605162. Its totient is φ = 866511756605160.

The previous prime is 866511756605141. The next prime is 866511756605167. The reversal of 866511756605161 is 161506657115668.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 815804981290000 + 50706775315161 = 28562300^2 + 7120869^2 .

It is a cyclic number.

It is not a de Polignac number, because 866511756605161 - 2¹⁵ = 866511756572393 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 866511756605093 and 866511756605102.

It is not a weakly prime, because it can be changed into another prime (866511756605167) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 433255878302580 + 433255878302581.

It is an arithmetic number, because the mean of its divisors is an integer number (433255878302581).

Almost surely, 2^{866511756605161} is an apocalyptic number.

It is an amenable number.

866511756605161 is a deficient number, since it is larger than the sum of its proper divisors (1).

866511756605161 is an equidigital number, since it uses as much as digits as its factorization.

866511756605161 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54432000, while the sum is 64.

The spelling of 866511756605161 in words is "eight hundred sixty-six trillion, five hundred eleven billion, seven hundred fifty-six million, six hundred five thousand, one hundred sixty-one".