221321221 has 12 divisors (see below), whose sum is σ = 245039200. Its totient is φ = 199738440.

The previous prime is 221321209. The next prime is 221321251. The reversal of 221321221 is 122123122.

It is a happy number.

It is not a de Polignac number, because 221321221 - 2¹¹ = 221319173 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 221321195 and 221321204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (221321251) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 10240 + ... + 23398.

Almost surely, 2^221321221 is an apocalyptic number.

It is an amenable number.

221321221 is a deficient number, since it is larger than the sum of its proper divisors (23717979).

221321221 is a wasteful number, since it uses less digits than its factorization.

221321221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13320 (or 13309 counting only the distinct ones).

The product of its digits is 96, while the sum is 16.

The square root of 221321221 is about 14876.8686557353. The cubic root of 221321221 is about 604.8871414828.

Adding to 221321221 its reverse (122123122), we get a palindrome (343444343).

The spelling of 221321221 in words is "two hundred twenty-one million, three hundred twenty-one thousand, two hundred twenty-one".