111811 has 4 divisors (see below), whose sum is σ = 127792. Its totient is φ = 95832.

The previous prime is 111799. The next prime is 111821. The reversal of 111811 is 118111.

111811 = 134² + 135² + ... + 139².

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 111811 - 2⁵ = 111779 is a prime.

111811 is a lucky number.

It is a junction number, because it is equal to n+sod(n) for n = 111791 and 111800.

It is not an unprimeable number, because it can be changed into a prime (111821) 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, 7980 + ... + 7993.

It is an arithmetic number, because the mean of its divisors is an integer number (31948).

2¹¹¹⁸¹¹ is an apocalyptic number.

111811 is a deficient number, since it is larger than the sum of its proper divisors (15981).

111811 is an equidigital number, since it uses as much as digits as its factorization.

111811 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 15980.

The product of its digits is 8, while the sum is 13.

The square root of 111811 is about 334.3815186280. The cubic root of 111811 is about 48.1757159170.

Adding to 111811 its reverse (118111), we get a palindrome (229922).

The spelling of 111811 in words is "one hundred eleven thousand, eight hundred eleven".