6405391 has 2 divisors, whose sum is σ = 6405392. Its totient is φ = 6405390.

The previous prime is 6405367. The next prime is 6405397. The reversal of 6405391 is 1935046.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 6405391 - 2⁷ = 6405263 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (6405397) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 3202695 + 3202696.

It is an arithmetic number, because the mean of its divisors is an integer number (3202696).

Almost surely, 2^6405391 is an apocalyptic number.

6405391 is a deficient number, since it is larger than the sum of its proper divisors (1).

6405391 is an equidigital number, since it uses as much as digits as its factorization.

6405391 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 3240, while the sum is 28.

The square root of 6405391 is about 2530.8873937811. The cubic root of 6405391 is about 185.7156695586.

The spelling of 6405391 in words is "six million, four hundred five thousand, three hundred ninety-one".