111155561 has 6 divisors (see below), whose sum is σ = 122179386. Its totient is φ = 101050400.

The previous prime is 111155557. The next prime is 111155563. The reversal of 111155561 is 165551111.

It can be written as a sum of positive squares in only one way, i.e., 91795561 + 19360000 = 9581^2 + 4400^2 .

It is not a de Polignac number, because 111155561 - 2² = 111155557 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 111155561.

It is not an unprimeable number, because it can be changed into a prime (111155563) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 459200 + ... + 459441.

It is an arithmetic number, because the mean of its divisors is an integer number (20363231).

Almost surely, 2^111155561 is an apocalyptic number.

111155561 is a gapful number since it is divisible by the number (11) formed by its first and last digit.

It is an amenable number.

111155561 is a deficient number, since it is larger than the sum of its proper divisors (11023825).

111155561 is an equidigital number, since it uses as much as digits as its factorization.

111155561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 918663 (or 918652 counting only the distinct ones).

The product of its digits is 750, while the sum is 26.

The square root of 111155561 is about 10543.0337664261. The cubic root of 111155561 is about 480.8139560554.

The spelling of 111155561 in words is "one hundred eleven million, one hundred fifty-five thousand, five hundred sixty-one".