6405809 has 4 divisors (see below), whose sum is σ = 6612480. Its totient is φ = 6199140.

The previous prime is 6405797. The next prime is 6405811. The reversal of 6405809 is 9085046.

6405809 is nontrivially palindromic in base 11.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 6405809 - 2¹² = 6401713 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (6405829) 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 in 3 ways as a sum of consecutive naturals, for example, 103289 + ... + 103350.

It is an arithmetic number, because the mean of its divisors is an integer number (1653120).

Almost surely, 2^6405809 is an apocalyptic number.

It is an amenable number.

6405809 is a deficient number, since it is larger than the sum of its proper divisors (206671).

6405809 is a wasteful number, since it uses less digits than its factorization.

6405809 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 206670.

The product of its (nonzero) digits is 8640, while the sum is 32.

The square root of 6405809 is about 2530.9699721648. The cubic root of 6405809 is about 185.7197092527.

The spelling of 6405809 in words is "six million, four hundred five thousand, eight hundred nine".