111809161 has 2 divisors, whose sum is σ = 111809162. Its totient is φ = 111809160.

The previous prime is 111809107. The next prime is 111809177. The reversal of 111809161 is 161908111.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 63297936 + 48511225 = 7956^2 + 6965^2 .

It is an emirp because it is prime and its reverse (161908111) is a distict prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-111809161 is a prime.

It is not a weakly prime, because it can be changed into another prime (111809101) 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 as a sum of consecutive naturals, namely, 55904580 + 55904581.

It is an arithmetic number, because the mean of its divisors is an integer number (55904581).

Almost surely, 2^111809161 is an apocalyptic number.

It is an amenable number.

111809161 is a deficient number, since it is larger than the sum of its proper divisors (1).

111809161 is an equidigital number, since it uses as much as digits as its factorization.

111809161 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 432, while the sum is 28.

The square root of 111809161 is about 10573.9851049640. The cubic root of 111809161 is about 481.7545179387.

The spelling of 111809161 in words is "one hundred eleven million, eight hundred nine thousand, one hundred sixty-one".