111161 has 4 divisors (see below), whose sum is σ = 112500. Its totient is φ = 109824.

The previous prime is 111149. The next prime is 111187. The reversal of 111161 is 161111.

111161 is nontrivially palindromic in base 4.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 161111 = 73 ⋅2207.

It can be written as a sum of positive squares in 2 ways, for example, as 32761 + 78400 = 181^2 + 280^2 .

It is a cyclic number.

It is not a de Polignac number, because 111161 - 2¹⁴ = 94777 is a prime.

It is an Ulam number.

It is a Duffinian number.

It is a Curzon number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 111161.

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, 536 + ... + 713.

It is an arithmetic number, because the mean of its divisors is an integer number (28125).

2¹¹¹¹⁶¹ is an apocalyptic number.

It is an amenable number.

111161 is a deficient number, since it is larger than the sum of its proper divisors (1339).

111161 is an equidigital number, since it uses as much as digits as its factorization.

111161 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1338.

The product of its digits is 6, while the sum is 11.

The square root of 111161 is about 333.4081582685. The cubic root of 111161 is about 48.0821798232.

Adding to 111161 its reverse (161111), we get a palindrome (272272).

It can be divided in two parts, 111 and 161, that multiplied together give a palindrome (17871).

The spelling of 111161 in words is "one hundred eleven thousand, one hundred sixty-one".