111243991 has 4 divisors (see below), whose sum is σ = 111318184. Its totient is φ = 111169800.

The previous prime is 111243989. The next prime is 111244009. The reversal of 111243991 is 199342111.

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 111243991 - 2¹ = 111243989 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 (111243901) 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, 34800 + ... + 37861.

It is an arithmetic number, because the mean of its divisors is an integer number (27829546).

Almost surely, 2^111243991 is an apocalyptic number.

111243991 is a deficient number, since it is larger than the sum of its proper divisors (74193).

111243991 is an equidigital number, since it uses as much as digits as its factorization.

111243991 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 74192.

The product of its digits is 1944, while the sum is 31.

The square root of 111243991 is about 10547.2266970991. The cubic root of 111243991 is about 480.9414263848.

The spelling of 111243991 in words is "one hundred eleven million, two hundred forty-three thousand, nine hundred ninety-one".