8722221 has 16 divisors (see below), whose sum is σ = 12289536. Its totient is φ = 5491376.

The previous prime is 8722211. The next prime is 8722223. The reversal of 8722221 is 1222278.

It is a happy number.

8722221 is digitally balanced in base 3, because in such base it contains all the possibile digits an equal number of times.

It is a cyclic number.

It is not a de Polignac number, because 8722221 - 2⁷ = 8722093 is a prime.

It is a Curzon number.

It is a nialpdrome in base 10.

It is a junction number, because it is equal to n+sod(n) for n = 8722191 and 8722200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (8722223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 4966 + ... + 6488.

It is an arithmetic number, because the mean of its divisors is an integer number (768096).

Almost surely, 2^8722221 is an apocalyptic number.

It is an amenable number.

8722221 is a deficient number, since it is larger than the sum of its proper divisors (3567315).

8722221 is a wasteful number, since it uses less digits than its factorization.

8722221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1632.

The product of its digits is 896, while the sum is 24.

The square root of 8722221 is about 2953.3406508562. The cubic root of 8722221 is about 205.8459667958.

Adding to 8722221 its reverse (1222278), we get a palindrome (9944499).

The spelling of 8722221 in words is "eight million, seven hundred twenty-two thousand, two hundred twenty-one".