8213221 has 2 divisors, whose sum is σ = 8213222. Its totient is φ = 8213220.

The previous prime is 8213207. The next prime is 8213267. The reversal of 8213221 is 1223128.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 4468996 + 3744225 = 2114^2 + 1935^2 .

It is a cyclic number.

It is not a de Polignac number, because 8213221 - 2⁵ = 8213189 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (8213291) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4106610 + 4106611.

It is an arithmetic number, because the mean of its divisors is an integer number (4106611).

Almost surely, 2^8213221 is an apocalyptic number.

It is an amenable number.

8213221 is a deficient number, since it is larger than the sum of its proper divisors (1).

8213221 is an equidigital number, since it uses as much as digits as its factorization.

8213221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 192, while the sum is 19.

The square root of 8213221 is about 2865.8717696366. The cubic root of 8213221 is about 201.7612855025.

Adding to 8213221 its reverse (1223128), we get a palindrome (9436349).

The spelling of 8213221 in words is "eight million, two hundred thirteen thousand, two hundred twenty-one".