6728009 has 2 divisors, whose sum is σ = 6728010. Its totient is φ = 6728008.

The previous prime is 6727993. The next prime is 6728011. The reversal of 6728009 is 9008276.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 3888784 + 2839225 = 1972^2 + 1685^2 .

It is a cyclic number.

It is not a de Polignac number, because 6728009 - 2⁴ = 6727993 is a prime.

It is a super-2 number, since 2×6728009² = 90532210208162, which contains 22 as substring.

Together with 6728011, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6728809) 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 as a sum of consecutive naturals, namely, 3364004 + 3364005.

It is an arithmetic number, because the mean of its divisors is an integer number (3364005).

Almost surely, 2^6728009 is an apocalyptic number.

It is an amenable number.

6728009 is a deficient number, since it is larger than the sum of its proper divisors (1).

6728009 is an equidigital number, since it uses as much as digits as its factorization.

6728009 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 6048, while the sum is 32.

The square root of 6728009 is about 2593.8405887795. The cubic root of 6728009 is about 188.7826977256.

The spelling of 6728009 in words is "six million, seven hundred twenty-eight thousand, nine".