4020221021 has 2 divisors, whose sum is σ = 4020221022. Its totient is φ = 4020221020.

The previous prime is 4020220993. The next prime is 4020221041. The reversal of 4020221021 is 1201220204.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 2492505625 + 1527715396 = 49925^2 + 39086^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-4020221021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 4020220987 and 4020221005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (4020221041) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 2010110510 + 2010110511.

It is an arithmetic number, because the mean of its divisors is an integer number (2010110511).

Almost surely, 2^4020221021 is an apocalyptic number.

It is an amenable number.

4020221021 is a deficient number, since it is larger than the sum of its proper divisors (1).

4020221021 is an equidigital number, since it uses as much as digits as its factorization.

4020221021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 14.

The square root of 4020221021 is about 63405.2128850617. The cubic root of 4020221021 is about 1590.0714629748.

Adding to 4020221021 its reverse (1201220204), we get a palindrome (5221441225).

The spelling of 4020221021 in words is "four billion, twenty million, two hundred twenty-one thousand, twenty-one".