22011221 has 2 divisors, whose sum is σ = 22011222. Its totient is φ = 22011220.

The previous prime is 22011211. The next prime is 22011239. The reversal of 22011221 is 12211022.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 19018321 + 2992900 = 4361^2 + 1730^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-22011221 is a prime.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (22011211) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 11005610 + 11005611.

It is an arithmetic number, because the mean of its divisors is an integer number (11005611).

Almost surely, 2^22011221 is an apocalyptic number.

It is an amenable number.

22011221 is a deficient number, since it is larger than the sum of its proper divisors (1).

22011221 is an equidigital number, since it uses as much as digits as its factorization.

22011221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 16, while the sum is 11.

The square root of 22011221 is about 4691.6117699571. The cubic root of 22011221 is about 280.2515638826.

Adding to 22011221 its reverse (12211022), we get a palindrome (34222243).

The spelling of 22011221 in words is "twenty-two million, eleven thousand, two hundred twenty-one".