1181958161 has 2 divisors, whose sum is σ = 1181958162. Its totient is φ = 1181958160.

The previous prime is 1181958149. The next prime is 1181958221. The reversal of 1181958161 is 1618591811.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 940342225 + 241615936 = 30665^2 + 15544^2 .

It is a cyclic number.

It is not a de Polignac number, because 1181958161 - 2¹⁰ = 1181957137 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is not a weakly prime, because it can be changed into another prime (1181958101) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 590979080 + 590979081.

It is an arithmetic number, because the mean of its divisors is an integer number (590979081).

Almost surely, 2^1181958161 is an apocalyptic number.

It is an amenable number.

1181958161 is a deficient number, since it is larger than the sum of its proper divisors (1).

1181958161 is an equidigital number, since it uses as much as digits as its factorization.

1181958161 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 17280, while the sum is 41.

The square root of 1181958161 is about 34379.6183952062. The cubic root of 1181958161 is about 1057.3060108745.

The spelling of 1181958161 in words is "one billion, one hundred eighty-one million, nine hundred fifty-eight thousand, one hundred sixty-one".