8121861161 has 2 divisors, whose sum is σ = 8121861162. Its totient is φ = 8121861160.

The previous prime is 8121861079. The next prime is 8121861169. The reversal of 8121861161 is 1611681218.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4104836761 + 4017024400 = 64069^2 + 63380^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-8121861161 is a prime.

It is not a weakly prime, because it can be changed into another prime (8121861169) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4060930580 + 4060930581.

It is an arithmetic number, because the mean of its divisors is an integer number (4060930581).

Almost surely, 2^8121861161 is an apocalyptic number.

It is an amenable number.

8121861161 is a deficient number, since it is larger than the sum of its proper divisors (1).

8121861161 is an equidigital number, since it uses as much as digits as its factorization.

8121861161 is an evil number, because the sum of its binary digits is even.

The product of its digits is 4608, while the sum is 35.

The square root of 8121861161 is about 90121.3690586201. The cubic root of 8121861161 is about 2010.1039657287.

The spelling of 8121861161 in words is "eight billion, one hundred twenty-one million, eight hundred sixty-one thousand, one hundred sixty-one".