6399209 has 2 divisors, whose sum is σ = 6399210. Its totient is φ = 6399208.

The previous prime is 6399193. The next prime is 6399251. The reversal of 6399209 is 9029936.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 6325225 + 73984 = 2515^2 + 272^2 .

It is a cyclic number.

It is not a de Polignac number, because 6399209 - 2⁴ = 6399193 is a prime.

It is not a weakly prime, because it can be changed into another prime (6399269) 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, 3199604 + 3199605.

It is an arithmetic number, because the mean of its divisors is an integer number (3199605).

Almost surely, 2^6399209 is an apocalyptic number.

It is an amenable number.

6399209 is a deficient number, since it is larger than the sum of its proper divisors (1).

6399209 is an equidigital number, since it uses as much as digits as its factorization.

6399209 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 26244, while the sum is 38.

The square root of 6399209 is about 2529.6657882021. The cubic root of 6399209 is about 185.6559040778.

The spelling of 6399209 in words is "six million, three hundred ninety-nine thousand, two hundred nine".