13205909 has 4 divisors (see below), whose sum is σ = 13354380. Its totient is φ = 13057440.

The previous prime is 13205891. The next prime is 13205953. The reversal of 13205909 is 90950231.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 90950231 = 1811 ⋅50221.

It can be written as a sum of positive squares in 2 ways, for example, as 1747684 + 11458225 = 1322^2 + 3385^2 .

It is a cyclic number.

It is not a de Polignac number, because 13205909 - 2⁸ = 13205653 is a prime.

It is a Duffinian number.

It is a plaindrome in base 15.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13205989) 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, 74102 + ... + 74279.

It is an arithmetic number, because the mean of its divisors is an integer number (3338595).

Almost surely, 2^13205909 is an apocalyptic number.

It is an amenable number.

13205909 is a deficient number, since it is larger than the sum of its proper divisors (148471).

13205909 is an equidigital number, since it uses as much as digits as its factorization.

13205909 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 148470.

The product of its (nonzero) digits is 2430, while the sum is 29.

The square root of 13205909 is about 3633.9935332909. The cubic root of 13205909 is about 236.3684097969.

The spelling of 13205909 in words is "thirteen million, two hundred five thousand, nine hundred nine".