8166521161 has 2 divisors, whose sum is σ = 8166521162. Its totient is φ = 8166521160.

The previous prime is 8166521141. The next prime is 8166521269. The reversal of 8166521161 is 1611256618.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 7646453136 + 520068025 = 87444^2 + 22805^2 .

It is a cyclic number.

It is not a de Polignac number, because 8166521161 - 2²⁵ = 8132966729 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 8166521161.

It is not a weakly prime, because it can be changed into another prime (8166521141) 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, 4083260580 + 4083260581.

It is an arithmetic number, because the mean of its divisors is an integer number (4083260581).

Almost surely, 2^8166521161 is an apocalyptic number.

It is an amenable number.

8166521161 is a deficient number, since it is larger than the sum of its proper divisors (1).

8166521161 is an equidigital number, since it uses as much as digits as its factorization.

8166521161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17280, while the sum is 37.

The square root of 8166521161 is about 90368.8063493150. The cubic root of 8166521161 is about 2013.7815793222.

Adding to 8166521161 its reverse (1611256618), we get a palindrome (9777777779).

The spelling of 8166521161 in words is "eight billion, one hundred sixty-six million, five hundred twenty-one thousand, one hundred sixty-one".