181121 has 4 divisors (see below), whose sum is σ = 183744. Its totient is φ = 178500.

The previous prime is 181087. The next prime is 181123. The reversal of 181121 is 121181.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 181121 - 2¹⁰ = 180097 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 181096 and 181105.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 181121.

It is not an unprimeable number, because it can be changed into a prime (181123) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1205 + ... + 1346.

It is an arithmetic number, because the mean of its divisors is an integer number (45936).

2¹⁸¹¹²¹ is an apocalyptic number.

It is an amenable number.

181121 is a deficient number, since it is larger than the sum of its proper divisors (2623).

181121 is an equidigital number, since it uses as much as digits as its factorization.

181121 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2622.

The product of its digits is 16, while the sum is 14.

The square root of 181121 is about 425.5831293649. The cubic root of 181121 is about 56.5791305147.

The spelling of 181121 in words is "one hundred eighty-one thousand, one hundred twenty-one".