111681 has 6 divisors (see below), whose sum is σ = 161330. Its totient is φ = 74448.

The previous prime is 111667. The next prime is 111697. The reversal of 111681 is 186111.

It can be written as a sum of positive squares in only one way, i.e., 65025 + 46656 = 255^2 + 216^2 .

It is a de Polignac number, because none of the positive numbers 2^k-111681 is a prime.

It is a super-2 number, since 2×111681² = 24945291522, which contains 22 as substring.

It is an Ulam number.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (111611) 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 5 ways as a sum of consecutive naturals, for example, 6196 + ... + 6213.

2¹¹¹⁶⁸¹ is an apocalyptic number.

It is an amenable number.

111681 is a deficient number, since it is larger than the sum of its proper divisors (49649).

111681 is a wasteful number, since it uses less digits than its factorization.

111681 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 12415 (or 12412 counting only the distinct ones).

The product of its digits is 48, while the sum is 18.

The square root of 111681 is about 334.1870733586. The cubic root of 111681 is about 48.1570377552.

Adding to 111681 its reverse (186111), we get a palindrome (297792).

The spelling of 111681 in words is "one hundred eleven thousand, six hundred eighty-one".