181091 has 4 divisors (see below), whose sum is σ = 184992. Its totient is φ = 177192.

The previous prime is 181087. The next prime is 181123. The reversal of 181091 is 190181.

181091 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes.

It is a cyclic number.

It is not a de Polignac number, because 181091 - 2² = 181087 is a prime.

It is not an unprimeable number, because it can be changed into a prime (181001) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1880 + ... + 1973.

It is an arithmetic number, because the mean of its divisors is an integer number (46248).

2¹⁸¹⁰⁹¹ is an apocalyptic number.

181091 is a deficient number, since it is larger than the sum of its proper divisors (3901).

181091 is an equidigital number, since it uses as much as digits as its factorization.

181091 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 3900.

The product of its (nonzero) digits is 72, while the sum is 20.

The square root of 181091 is about 425.5478821472. The cubic root of 181091 is about 56.5760065117.

The spelling of 181091 in words is "one hundred eighty-one thousand, ninety-one".