6403905 has 24 divisors (see below), whose sum is σ = 11217960. Its totient is φ = 3379200.

The previous prime is 6403889. The next prime is 6403907. The reversal of 6403905 is 5093046.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 484416 + 5919489 = 696^2 + 2433^2 .

It is not a de Polignac number, because 6403905 - 2⁴ = 6403889 is a prime.

It is a Smith number, since the sum of its digits (27) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a prime (6403907) 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 23 ways as a sum of consecutive naturals, for example, 3841 + ... + 5249.

It is an arithmetic number, because the mean of its divisors is an integer number (467415).

Almost surely, 2^6403905 is an apocalyptic number.

It is an amenable number.

6403905 is a deficient number, since it is larger than the sum of its proper divisors (4814055).

6403905 is a wasteful number, since it uses less digits than its factorization.

6403905 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1521 (or 1518 counting only the distinct ones).

The product of its (nonzero) digits is 3240, while the sum is 27.

The square root of 6403905 is about 2530.5938038334. The cubic root of 6403905 is about 185.7013069262.

The spelling of 6403905 in words is "six million, four hundred three thousand, nine hundred five".