2161220111 has 2 divisors, whose sum is σ = 2161220112. Its totient is φ = 2161220110.

The previous prime is 2161220077. The next prime is 2161220123. The reversal of 2161220111 is 1110221612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2161220111 - 2²⁶ = 2094111247 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 2161220111.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2161220161) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1080610055 + 1080610056.

It is an arithmetic number, because the mean of its divisors is an integer number (1080610056).

Almost surely, 2^2161220111 is an apocalyptic number.

2161220111 is a deficient number, since it is larger than the sum of its proper divisors (1).

2161220111 is an equidigital number, since it uses as much as digits as its factorization.

2161220111 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 17.

The square root of 2161220111 is about 46488.9246057596. The cubic root of 2161220111 is about 1292.9041616742.

Adding to 2161220111 its reverse (1110221612), we get a palindrome (3271441723).

The spelling of 2161220111 in words is "two billion, one hundred sixty-one million, two hundred twenty thousand, one hundred eleven".