2100909 has 4 divisors (see below), whose sum is σ = 2801216. Its totient is φ = 1400604.

The previous prime is 2100899. The next prime is 2100913. The reversal of 2100909 is 9090012.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is not a de Polignac number, because 2100909 - 2⁴ = 2100893 is a prime.

It is a D-number.

It is a Duffinian number.

2100909 is a modest number, since divided by 909 gives 210 as remainder.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2100929) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 350149 + ... + 350154.

It is an arithmetic number, because the mean of its divisors is an integer number (700304).

2^2100909 is an apocalyptic number.

It is an amenable number.

2100909 is a deficient number, since it is larger than the sum of its proper divisors (700307).

2100909 is an equidigital number, since it uses as much as digits as its factorization.

2100909 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 700306.

The product of its (nonzero) digits is 162, while the sum is 21.

The square root of 2100909 is about 1449.4512754832. The cubic root of 2100909 is about 128.0763907614.

The spelling of 2100909 in words is "two million, one hundred thousand, nine hundred nine".