13509409 has 4 divisors (see below), whose sum is σ = 13520304. Its totient is φ = 13498516.

The previous prime is 13509401. The next prime is 13509413. The reversal of 13509409 is 90490531.

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, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 90490531 = 149 ⋅607319.

It is a cyclic number.

It is not a de Polignac number, because 13509409 - 2³ = 13509401 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (13509401) 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, 3307 + ... + 6160.

It is an arithmetic number, because the mean of its divisors is an integer number (3380076).

Almost surely, 2^13509409 is an apocalyptic number.

It is an amenable number.

13509409 is a deficient number, since it is larger than the sum of its proper divisors (10895).

13509409 is an equidigital number, since it uses as much as digits as its factorization.

13509409 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10894.

The product of its (nonzero) digits is 4860, while the sum is 31.

The square root of 13509409 is about 3675.5147938758. The cubic root of 13509409 is about 238.1654629357.

The spelling of 13509409 in words is "thirteen million, five hundred nine thousand, four hundred nine".