9819221 has 2 divisors, whose sum is σ = 9819222. Its totient is φ = 9819220.

The previous prime is 9819211. The next prime is 9819223. The reversal of 9819221 is 1229189.

It is a happy number.

9819221 is digitally balanced in base 2, because in such base it contains all the possibile digits an equal number of times.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 8584900 + 1234321 = 2930^2 + 1111^2 .

It is a cyclic number.

It is not a de Polignac number, because 9819221 - 2²² = 5624917 is a prime.

Together with 9819223, it forms a pair of twin primes.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (9819223) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 4909610 + 4909611.

It is an arithmetic number, because the mean of its divisors is an integer number (4909611).

Almost surely, 2^9819221 is an apocalyptic number.

It is an amenable number.

9819221 is a deficient number, since it is larger than the sum of its proper divisors (1).

9819221 is an equidigital number, since it uses as much as digits as its factorization.

9819221 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2592, while the sum is 32.

The square root of 9819221 is about 3133.5636262888. The cubic root of 9819221 is about 214.1373110674.

Subtracting from 9819221 its sum of digits (32), we obtain a palindrome (9819189).

The spelling of 9819221 in words is "nine million, eight hundred nineteen thousand, two hundred twenty-one".