6566421 has 4 divisors (see below), whose sum is σ = 8755232. Its totient is φ = 4377612.

The previous prime is 6566407. The next prime is 6566453. The reversal of 6566421 is 1246656.

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 6566421 - 2¹³ = 6558229 is a prime.

It is a D-number.

It is a Duffinian number.

It is a Curzon number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6566621) 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, 1094401 + ... + 1094406.

It is an arithmetic number, because the mean of its divisors is an integer number (2188808).

Almost surely, 2^6566421 is an apocalyptic number.

It is an amenable number.

6566421 is a deficient number, since it is larger than the sum of its proper divisors (2188811).

6566421 is a wasteful number, since it uses less digits than its factorization.

6566421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2188810.

The product of its digits is 8640, while the sum is 30.

The square root of 6566421 is about 2562.5028780472. The cubic root of 6566421 is about 187.2590897089.

The spelling of 6566421 in words is "six million, five hundred sixty-six thousand, four hundred twenty-one".