2181889 has 2 divisors, whose sum is σ = 2181890. Its totient is φ = 2181888.

The previous prime is 2181871. The next prime is 2181919. The reversal of 2181889 is 9881812.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1703025 + 478864 = 1305^2 + 692^2 .

It is a cyclic number.

It is not a de Polignac number, because 2181889 - 2⁵ = 2181857 is a prime.

It is a Chen prime.

2181889 is a lucky number.

It is not a weakly prime, because it can be changed into another prime (2181869) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1090944 + 1090945.

It is an arithmetic number, because the mean of its divisors is an integer number (1090945).

2^2181889 is an apocalyptic number.

It is an amenable number.

2181889 is a deficient number, since it is larger than the sum of its proper divisors (1).

2181889 is an equidigital number, since it uses as much as digits as its factorization.

2181889 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 9216, while the sum is 37.

The square root of 2181889 is about 1477.1218636253. The cubic root of 2181889 is about 129.7012667149.

The spelling of 2181889 in words is "two million, one hundred eighty-one thousand, eight hundred eighty-nine".