6409821 has 16 divisors (see below), whose sum is σ = 9815040. Its totient is φ = 3679920.

The previous prime is 6409807. The next prime is 6409849. The reversal of 6409821 is 1289046.

It is not a de Polignac number, because 6409821 - 2⁶ = 6409757 is a prime.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6409321) 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 15 ways as a sum of consecutive naturals, for example, 4485 + ... + 5738.

It is an arithmetic number, because the mean of its divisors is an integer number (613440).

Almost surely, 2^6409821 is an apocalyptic number.

It is an amenable number.

6409821 is a deficient number, since it is larger than the sum of its proper divisors (3405219).

6409821 is a wasteful number, since it uses less digits than its factorization.

6409821 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 10256.

The product of its (nonzero) digits is 3456, while the sum is 30.

The square root of 6409821 is about 2531.7624296130. The cubic root of 6409821 is about 185.7584736499.

The spelling of 6409821 in words is "six million, four hundred nine thousand, eight hundred twenty-one".