6628221 has 6 divisors (see below), whose sum is σ = 9574110. Its totient is φ = 4418808.

The previous prime is 6628201. The next prime is 6628247. The reversal of 6628221 is 1228266.

It can be written as a sum of positive squares in only one way, i.e., 6320196 + 308025 = 2514^2 + 555^2 .

It is not a de Polignac number, because 6628221 - 2⁵ = 6628189 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 (6628201) 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 5 ways as a sum of consecutive naturals, for example, 368226 + ... + 368243.

It is an arithmetic number, because the mean of its divisors is an integer number (1595685).

Almost surely, 2^6628221 is an apocalyptic number.

It is an amenable number.

6628221 is a deficient number, since it is larger than the sum of its proper divisors (2945889).

6628221 is a wasteful number, since it uses less digits than its factorization.

6628221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 736475 (or 736472 counting only the distinct ones).

The product of its digits is 2304, while the sum is 27.

The square root of 6628221 is about 2574.5331615654. The cubic root of 6628221 is about 187.8447205064.

The spelling of 6628221 in words is "six million, six hundred twenty-eight thousand, two hundred twenty-one".