111981861 has 6 divisors (see below), whose sum is σ = 161751590. Its totient is φ = 74654568.

The previous prime is 111981853. The next prime is 111981901. The reversal of 111981861 is 168189111.

It can be written as a sum of positive squares in only one way, i.e., 106193025 + 5788836 = 10305^2 + 2406^2 .

It is not a de Polignac number, because 111981861 - 2³ = 111981853 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (111981811) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 6221206 + ... + 6221223.

Almost surely, 2^111981861 is an apocalyptic number.

It is an amenable number.

111981861 is a deficient number, since it is larger than the sum of its proper divisors (49769729).

111981861 is a wasteful number, since it uses less digits than its factorization.

111981861 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 12442435 (or 12442432 counting only the distinct ones).

The product of its digits is 3456, while the sum is 36.

The square root of 111981861 is about 10582.1482223601. The cubic root of 111981861 is about 482.0024290667.

The spelling of 111981861 in words is "one hundred eleven million, nine hundred eighty-one thousand, eight hundred sixty-one".