111991568 has 60 divisors (see below), whose sum is σ = 238266000. Its totient is φ = 50963328.

The previous prime is 111991549. The next prime is 111991571. The reversal of 111991568 is 865199111.

It is a happy number.

It is a super-2 number, since 2×111991568² = 25084222606197248, which contains 22 as substring.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 224183 + ... + 224681.

It is an arithmetic number, because the mean of its divisors is an integer number (3971100).

Almost surely, 2^111991568 is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 111991568, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (119133000).

111991568 is an abundant number, since it is smaller than the sum of its proper divisors (126274432).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

111991568 is a wasteful number, since it uses less digits than its factorization.

111991568 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 616 (or 597 counting only the distinct ones).

The product of its digits is 19440, while the sum is 41.

The square root of 111991568 is about 10582.6068622056. The cubic root of 111991568 is about 482.0163559127.

The spelling of 111991568 in words is "one hundred eleven million, nine hundred ninety-one thousand, five hundred sixty-eight".