13664509 has 4 divisors (see below), whose sum is σ = 13672960. Its totient is φ = 13656060.

The previous prime is 13664491. The next prime is 13664527. The reversal of 13664509 is 90546631.

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.

It is an interprime number because it is at equal distance from previous prime (13664491) and next prime (13664527).

It is a cyclic number.

It is not a de Polignac number, because 13664509 - 2⁹ = 13663997 is a prime.

It is a super-2 number, since 2×13664509² = 373437612422162, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (13664569) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 957 + ... + 5314.

It is an arithmetic number, because the mean of its divisors is an integer number (3418240).

Almost surely, 2^13664509 is an apocalyptic number.

It is an amenable number.

13664509 is a deficient number, since it is larger than the sum of its proper divisors (8451).

13664509 is an equidigital number, since it uses as much as digits as its factorization.

13664509 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 8450.

The product of its (nonzero) digits is 19440, while the sum is 34.

The square root of 13664509 is about 3696.5536652401. The cubic root of 13664509 is about 239.0734471955.

The spelling of 13664509 in words is "thirteen million, six hundred sixty-four thousand, five hundred nine".