2111809 has 16 divisors (see below), whose sum is σ = 2545920. Its totient is φ = 1713600.

The previous prime is 2111803. The next prime is 2111819. The reversal of 2111809 is 9081112.

It is not a de Polignac number, because 2111809 - 2³ = 2111801 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 2111809.

It is not an unprimeable number, because it can be changed into a prime (2111801) 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 in 15 ways as a sum of consecutive naturals, for example, 20452 + ... + 20554.

It is an arithmetic number, because the mean of its divisors is an integer number (159120).

2^2111809 is an apocalyptic number.

2111809 is a gapful number since it is divisible by the number (29) formed by its first and last digit.

It is an amenable number.

2111809 is a deficient number, since it is larger than the sum of its proper divisors (434111).

2111809 is a wasteful number, since it uses less digits than its factorization.

2111809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 240.

The product of its (nonzero) digits is 144, while the sum is 22.

The square root of 2111809 is about 1453.2064547063. The cubic root of 2111809 is about 128.2975054124.

The spelling of 2111809 in words is "two million, one hundred eleven thousand, eight hundred nine".