6404809 has 2 divisors, whose sum is σ = 6404810. Its totient is φ = 6404808.

The previous prime is 6404791. The next prime is 6404819. The reversal of 6404809 is 9084046.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 5760000 + 644809 = 2400^2 + 803^2 .

It is a cyclic number.

It is not a de Polignac number, because 6404809 - 2⁵ = 6404777 is a prime.

It is equal to p₄₃₈₇₁₈ and since 6404809 and 438718 have the same sum of digits, it is a Honaker prime.

It is not a weakly prime, because it can be changed into another prime (6404819) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3202404 + 3202405.

It is an arithmetic number, because the mean of its divisors is an integer number (3202405).

Almost surely, 2^6404809 is an apocalyptic number.

It is an amenable number.

6404809 is a deficient number, since it is larger than the sum of its proper divisors (1).

6404809 is an equidigital number, since it uses as much as digits as its factorization.

6404809 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 6912, while the sum is 31.

The square root of 6404809 is about 2530.7724117352. The cubic root of 6404809 is about 185.7100446200.

The spelling of 6404809 in words is "six million, four hundred four thousand, eight hundred nine".