6817221 has 18 divisors (see below), whose sum is σ = 10464402. Its totient is φ = 4275840.

The previous prime is 6817211. The next prime is 6817243. The reversal of 6817221 is 1227186.

It can be written as a sum of positive squares in 3 ways, for example, as 3944196 + 2873025 = 1986^2 + 1695^2 .

It is not a de Polignac number, because 6817221 - 2⁶ = 6817157 is a prime.

6817221 is a lucky number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (6817211) by changing a digit.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 1291 + ... + 3911.

Almost surely, 2^6817221 is an apocalyptic number.

It is an amenable number.

6817221 is a deficient number, since it is larger than the sum of its proper divisors (3647181).

6817221 is a wasteful number, since it uses less digits than its factorization.

6817221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2661 (or 2641 counting only the distinct ones).

The product of its digits is 1344, while the sum is 27.

The square root of 6817221 is about 2610.9808501787. The cubic root of 6817221 is about 189.6134430729.

The spelling of 6817221 in words is "six million, eight hundred seventeen thousand, two hundred twenty-one".