161711111 has 2 divisors, whose sum is σ = 161711112. Its totient is φ = 161711110.

The previous prime is 161711107. The next prime is 161711113. The reversal of 161711111 is 111117161.

It is a strong prime.

It is an emirp because it is prime and its reverse (111117161) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 161711111 - 2² = 161711107 is a prime.

It is a Sophie Germain prime.

Together with 161711113, it forms a pair of twin primes.

It is a Chen prime.

161711111 is a modest number, since divided by 11111 gives 1617 as remainder.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (161711113) 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, 80855555 + 80855556.

It is an arithmetic number, because the mean of its divisors is an integer number (80855556).

Almost surely, 2^161711111 is an apocalyptic number.

161711111 is a deficient number, since it is larger than the sum of its proper divisors (1).

161711111 is an equidigital number, since it uses as much as digits as its factorization.

161711111 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 42, while the sum is 20.

The square root of 161711111 is about 12716.5683657188. The cubic root of 161711111 is about 544.8119442077.

Adding to 161711111 its reverse (111117161), we get a palindrome (272828272).

The spelling of 161711111 in words is "one hundred sixty-one million, seven hundred eleven thousand, one hundred eleven".