1161326891 has 2 divisors, whose sum is σ = 1161326892. Its totient is φ = 1161326890.

The previous prime is 1161326861. The next prime is 1161326893. The reversal of 1161326891 is 1986231611.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 1161326891 - 2³⁰ = 87585067 is a prime.

It is a Sophie Germain prime.

Together with 1161326893, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (1161326893) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 580663445 + 580663446.

It is an arithmetic number, because the mean of its divisors is an integer number (580663446).

Almost surely, 2^1161326891 is an apocalyptic number.

1161326891 is a deficient number, since it is larger than the sum of its proper divisors (1).

1161326891 is an equidigital number, since it uses as much as digits as its factorization.

1161326891 is an evil number, because the sum of its binary digits is even.

The product of its digits is 15552, while the sum is 38.

The square root of 1161326891 is about 34078.2465951522. The cubic root of 1161326891 is about 1051.1180504871.

The spelling of 1161326891 in words is "one billion, one hundred sixty-one million, three hundred twenty-six thousand, eight hundred ninety-one".