222220021 has 2 divisors, whose sum is σ = 222220022. Its totient is φ = 222220020.

The previous prime is 222220013. The next prime is 222220027. The reversal of 222220021 is 120022222.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 153412996 + 68807025 = 12386^2 + 8295^2 .

It is a cyclic number.

It is not a de Polignac number, because 222220021 - 2³ = 222220013 is a prime.

It is a Chen prime.

It is a junction number, because it is equal to n+sod(n) for n = 222219983 and 222220010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (222220027) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 111110010 + 111110011.

It is an arithmetic number, because the mean of its divisors is an integer number (111110011).

Almost surely, 2^222220021 is an apocalyptic number.

It is an amenable number.

222220021 is a deficient number, since it is larger than the sum of its proper divisors (1).

222220021 is an equidigital number, since it uses as much as digits as its factorization.

222220021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 64, while the sum is 13.

The square root of 222220021 is about 14907.0460185779. The cubic root of 222220021 is about 605.7048643277.

Adding to 222220021 its reverse (120022222), we get a palindrome (342242243).

The spelling of 222220021 in words is "two hundred twenty-two million, two hundred twenty thousand, twenty-one".