222121021 has 2 divisors, whose sum is σ = 222121022. Its totient is φ = 222121020.

The previous prime is 222121007. The next prime is 222121033. The reversal of 222121021 is 120121222.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 188073796 + 34047225 = 13714^2 + 5835^2 .

It is a cyclic number.

It is not a de Polignac number, because 222121021 - 2¹³ = 222112829 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 222120992 and 222121010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (222121721) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 111060510 + 111060511.

It is an arithmetic number, because the mean of its divisors is an integer number (111060511).

Almost surely, 2^222121021 is an apocalyptic number.

It is an amenable number.

222121021 is a deficient number, since it is larger than the sum of its proper divisors (1).

222121021 is an equidigital number, since it uses as much as digits as its factorization.

222121021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 13.

The square root of 222121021 is about 14903.7250712699. The cubic root of 222121021 is about 605.6149029036.

Adding to 222121021 its reverse (120121222), we get a palindrome (342242243).

The spelling of 222121021 in words is "two hundred twenty-two million, one hundred twenty-one thousand, twenty-one".