6639609 has 4 divisors (see below), whose sum is σ = 8852816. Its totient is φ = 4426404.

The previous prime is 6639601. The next prime is 6639629. The reversal of 6639609 is 9069366.

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 6639609 - 2³ = 6639601 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is not an unprimeable number, because it can be changed into a prime (6639601) 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, 1106599 + ... + 1106604.

It is an arithmetic number, because the mean of its divisors is an integer number (2213204).

Almost surely, 2^6639609 is an apocalyptic number.

It is an amenable number.

6639609 is a deficient number, since it is larger than the sum of its proper divisors (2213207).

6639609 is a wasteful number, since it uses less digits than its factorization.

6639609 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2213206.

The product of its (nonzero) digits is 52488, while the sum is 39.

The square root of 6639609 is about 2576.7438755142. The cubic root of 6639609 is about 187.9522381311.

The spelling of 6639609 in words is "six million, six hundred thirty-nine thousand, six hundred nine".