2099809 has 2 divisors, whose sum is σ = 2099810. Its totient is φ = 2099808.

The previous prime is 2099771. The next prime is 2099821. The reversal of 2099809 is 9089902.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 1149184 + 950625 = 1072^2 + 975^2 .

It is a cyclic number.

It is not a de Polignac number, because 2099809 - 2¹⁵ = 2067041 is a prime.

It is not a weakly prime, because it can be changed into another prime (2099309) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 1049904 + 1049905.

It is an arithmetic number, because the mean of its divisors is an integer number (1049905).

2^2099809 is an apocalyptic number.

It is an amenable number.

2099809 is a deficient number, since it is larger than the sum of its proper divisors (1).

2099809 is an equidigital number, since it uses as much as digits as its factorization.

2099809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 11664, while the sum is 37.

The square root of 2099809 is about 1449.0717718595. The cubic root of 2099809 is about 128.0540339902.

The spelling of 2099809 in words is "two million, ninety-nine thousand, eight hundred nine".