2105209 has 2 divisors, whose sum is σ = 2105210. Its totient is φ = 2105208.

The previous prime is 2105203. The next prime is 2105231. The reversal of 2105209 is 9025012.

2105209 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 1432809 + 672400 = 1197^2 + 820^2 .

It is a cyclic number.

It is not a de Polignac number, because 2105209 - 2¹⁹ = 1580921 is a prime.

It is not a weakly prime, because it can be changed into another prime (2105203) 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, 1052604 + 1052605.

It is an arithmetic number, because the mean of its divisors is an integer number (1052605).

2^2105209 is an apocalyptic number.

It is an amenable number.

2105209 is a deficient number, since it is larger than the sum of its proper divisors (1).

2105209 is an equidigital number, since it uses as much as digits as its factorization.

2105209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 180, while the sum is 19.

The square root of 2105209 is about 1450.9338372235. The cubic root of 2105209 is about 128.1637106113.

The spelling of 2105209 in words is "two million, one hundred five thousand, two hundred nine".