4020221 has 2 divisors, whose sum is σ = 4020222. Its totient is φ = 4020220.

The previous prime is 4020217. The next prime is 4020223. The reversal of 4020221 is 1220204.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 4020025 + 196 = 2005^2 + 14^2 .

It is a cyclic number.

It is not a de Polignac number, because 4020221 - 2² = 4020217 is a prime.

It is a Sophie Germain prime.

Together with 4020223, it forms a pair of twin primes.

It is a Chen prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4020223) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a good prime.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2010110 + 2010111.

It is an arithmetic number, because the mean of its divisors is an integer number (2010111).

Almost surely, 2^4020221 is an apocalyptic number.

It is an amenable number.

4020221 is a deficient number, since it is larger than the sum of its proper divisors (1).

4020221 is an equidigital number, since it uses as much as digits as its factorization.

4020221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 32, while the sum is 11.

The square root of 4020221 is about 2005.0488772097. The cubic root of 4020221 is about 159.0071460206.

Adding to 4020221 its reverse (1220204), we get a palindrome (5240425).

The spelling of 4020221 in words is "four million, twenty thousand, two hundred twenty-one".