8211221 has 8 divisors (see below), whose sum is σ = 8817984. Its totient is φ = 7618240.

The previous prime is 8211197. The next prime is 8211227. The reversal of 8211221 is 1221128.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 8211221 - 2¹⁰ = 8210197 is a prime.

It is a Harshad number since it is a multiple of its sum of digits (17).

It is a Duffinian number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 8211221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8211227) 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 7 ways as a sum of consecutive naturals, for example, 2195 + ... + 4608.

It is an arithmetic number, because the mean of its divisors is an integer number (1102248).

Almost surely, 2^8211221 is an apocalyptic number.

It is an amenable number.

8211221 is a deficient number, since it is larger than the sum of its proper divisors (606763).

8211221 is a wasteful number, since it uses less digits than its factorization.

8211221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6891.

The product of its digits is 64, while the sum is 17.

The square root of 8211221 is about 2865.5228144267. The cubic root of 8211221 is about 201.7449072213.

Adding to 8211221 its reverse (1221128), we get a palindrome (9432349).

The spelling of 8211221 in words is "eight million, two hundred eleven thousand, two hundred twenty-one".