20204221 has 2 divisors, whose sum is σ = 20204222. Its totient is φ = 20204220.

The previous prime is 20204209. The next prime is 20204231. The reversal of 20204221 is 12240202.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19263321 + 940900 = 4389^2 + 970^2 .

It is a cyclic number.

It is not a de Polignac number, because 20204221 - 2⁹ = 20203709 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20204231) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (13) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10102110 + 10102111.

It is an arithmetic number, because the mean of its divisors is an integer number (10102111).

Almost surely, 2^20204221 is an apocalyptic number.

It is an amenable number.

20204221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20204221 is an equidigital number, since it uses as much as digits as its factorization.

20204221 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 20204221 is about 4494.9105664073. The cubic root of 20204221 is about 272.3625365090.

Adding to 20204221 its reverse (12240202), we get a palindrome (32444423).

It can be divided in two parts, 2020 and 4221, that added together give a square (6241 = 79²).

The spelling of 20204221 in words is "twenty million, two hundred four thousand, two hundred twenty-one".