161191 has 4 divisors (see below), whose sum is σ = 162000. Its totient is φ = 160384.

The previous prime is 161167. The next prime is 161201. The reversal of 161191 is 191161.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length.

It is a cyclic number.

It is not a de Polignac number, because 161191 - 2⁵ = 161159 is a prime.

161191 is a strobogrammatic number because it is the same when read upside-down.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (161141) 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 in 3 ways as a sum of consecutive naturals, for example, 135 + ... + 583.

It is an arithmetic number, because the mean of its divisors is an integer number (40500).

2¹⁶¹¹⁹¹ is an apocalyptic number.

161191 is a deficient number, since it is larger than the sum of its proper divisors (809).

161191 is an equidigital number, since it uses as much as digits as its factorization.

161191 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 808.

The product of its digits is 54, while the sum is 19.

The square root of 161191 is about 401.4859897929. The cubic root of 161191 is about 54.4227224497.

The spelling of 161191 in words is "one hundred sixty-one thousand, one hundred ninety-one".