111111100610561 has 4 divisors (see below), whose sum is σ = 111111125883972. Its totient is φ = 111111075337152.

The previous prime is 111111100610483. The next prime is 111111100610599. The reversal of 111111100610561 is 165016001111111.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 54764158878961 + 56346941731600 = 7400281^2 + 7506460^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-111111100610561 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 111111100610561.

It is not an unprimeable number, because it can be changed into a prime (111111100810561) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 4136036 + ... + 15470261.

It is an arithmetic number, because the mean of its divisors is an integer number (27777781470993).

Almost surely, 2^{111111100610561} is an apocalyptic number.

It is an amenable number.

111111100610561 is a deficient number, since it is larger than the sum of its proper divisors (25273411).

111111100610561 is an equidigital number, since it uses as much as digits as its factorization.

111111100610561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 25273410.

The product of its (nonzero) digits is 180, while the sum is 26.

Adding to 111111100610561 its reverse (165016001111111), we get a palindrome (276127101721672).

The spelling of 111111100610561 in words is "one hundred eleven trillion, one hundred eleven billion, one hundred million, six hundred ten thousand, five hundred sixty-one".