6406221 has 4 divisors (see below), whose sum is σ = 8541632. Its totient is φ = 4270812.

The previous prime is 6406219. The next prime is 6406247. The reversal of 6406221 is 1226046.

It is a happy number.

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 not a de Polignac number, because 6406221 - 2¹ = 6406219 is a prime.

It is a D-number.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6406321) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1067701 + ... + 1067706.

It is an arithmetic number, because the mean of its divisors is an integer number (2135408).

Almost surely, 2^6406221 is an apocalyptic number.

It is an amenable number.

6406221 is a deficient number, since it is larger than the sum of its proper divisors (2135411).

6406221 is a wasteful number, since it uses less digits than its factorization.

6406221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2135410.

The product of its (nonzero) digits is 576, while the sum is 21.

The square root of 6406221 is about 2531.0513625764. The cubic root of 6406221 is about 185.7236907888.

The spelling of 6406221 in words is "six million, four hundred six thousand, two hundred twenty-one".