111110101561 has 2 divisors, whose sum is σ = 111110101562. Its totient is φ = 111110101560.

The previous prime is 111110101489. The next prime is 111110101567. The reversal of 111110101561 is 165101011111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 96792543225 + 14317558336 = 311115^2 + 119656^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-111110101561 is a prime.

It is not a weakly prime, because it can be changed into another prime (111110101567) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 55555050780 + 55555050781.

It is an arithmetic number, because the mean of its divisors is an integer number (55555050781).

Almost surely, 2^111110101561 is an apocalyptic number.

It is an amenable number.

111110101561 is a deficient number, since it is larger than the sum of its proper divisors (1).

111110101561 is an equidigital number, since it uses as much as digits as its factorization.

111110101561 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 30, while the sum is 19.

Adding to 111110101561 its reverse (165101011111), we get a palindrome (276211112672).

The spelling of 111110101561 in words is "one hundred eleven billion, one hundred ten million, one hundred one thousand, five hundred sixty-one".