2105309 has 4 divisors (see below), whose sum is σ = 2156700. Its totient is φ = 2053920.

The previous prime is 2105287. The next prime is 2105317. The reversal of 2105309 is 9035012.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 136900 + 1968409 = 370^2 + 1403^2 .

It is a cyclic number.

It is not a de Polignac number, because 2105309 - 2¹² = 2101213 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (2105329) 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, 25634 + ... + 25715.

It is an arithmetic number, because the mean of its divisors is an integer number (539175).

2^2105309 is an apocalyptic number.

It is an amenable number.

2105309 is a deficient number, since it is larger than the sum of its proper divisors (51391).

2105309 is an equidigital number, since it uses as much as digits as its factorization.

2105309 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 51390.

The product of its (nonzero) digits is 270, while the sum is 20.

The square root of 2105309 is about 1450.9682973794. The cubic root of 2105309 is about 128.1657398901.

The spelling of 2105309 in words is "two million, one hundred five thousand, three hundred nine".