2161823 has 2 divisors, whose sum is σ = 2161824. Its totient is φ = 2161822.

The previous prime is 2161813. The next prime is 2161829. The reversal of 2161823 is 3281612.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 2161823 - 2⁶ = 2161759 is a prime.

It is a Sophie Germain prime.

It is an Ulam number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (2161829) 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, 1080911 + 1080912.

It is an arithmetic number, because the mean of its divisors is an integer number (1080912).

2^2161823 is an apocalyptic number.

2161823 is a deficient number, since it is larger than the sum of its proper divisors (1).

2161823 is an equidigital number, since it uses as much as digits as its factorization.

2161823 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 576, while the sum is 23.

The square root of 2161823 is about 1470.3139120610. The cubic root of 2161823 is about 129.3024372356.

The spelling of 2161823 in words is "two million, one hundred sixty-one thousand, eight hundred twenty-three".