6440309 has 4 divisors (see below), whose sum is σ = 6452160. Its totient is φ = 6428460.

The previous prime is 6440303. The next prime is 6440311. The reversal of 6440309 is 9030446.

6440309 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

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 a cyclic number.

It is not a de Polignac number, because 6440309 - 2²⁰ = 5391733 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 (6440303) 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, 5069 + ... + 6210.

It is an arithmetic number, because the mean of its divisors is an integer number (1613040).

Almost surely, 2^6440309 is an apocalyptic number.

It is an amenable number.

6440309 is a deficient number, since it is larger than the sum of its proper divisors (11851).

6440309 is a wasteful number, since it uses less digits than its factorization.

6440309 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 11850.

The product of its (nonzero) digits is 2592, while the sum is 26.

The square root of 6440309 is about 2537.7763888885. The cubic root of 6440309 is about 186.0525249586.

The spelling of 6440309 in words is "six million, four hundred forty thousand, three hundred nine".