111921 has 4 divisors (see below), whose sum is σ = 149232. Its totient is φ = 74612.

The previous prime is 111919. The next prime is 111949. The reversal of 111921 is 129111.

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, and also an emirpimes, since its reverse is a distinct semiprime: 129111 = 3 ⋅43037.

It is a cyclic number.

It is not a de Polignac number, because 111921 - 2¹ = 111919 is a prime.

It is an Ulam number.

It is a D-number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 111921.

It is not an unprimeable number, because it can be changed into a prime (111121) 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, 18651 + ... + 18656.

It is an arithmetic number, because the mean of its divisors is an integer number (37308).

2¹¹¹⁹²¹ is an apocalyptic number.

It is an amenable number.

111921 is a deficient number, since it is larger than the sum of its proper divisors (37311).

111921 is an equidigital number, since it uses as much as digits as its factorization.

111921 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 37310.

The product of its digits is 18, while the sum is 15.

The square root of 111921 is about 334.5459609680. The cubic root of 111921 is about 48.1915092107.

The spelling of 111921 in words is "one hundred eleven thousand, nine hundred twenty-one".