20021210202221 has 2 divisors, whose sum is σ = 20021210202222. Its totient is φ = 20021210202220.

The previous prime is 20021210202181. The next prime is 20021210202289. The reversal of 20021210202221 is 12220201212002.

It is a happy number.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 18450547068100 + 1570663134121 = 4295410^2 + 1253261^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-20021210202221 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 20021210202221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20021210252221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10010605101110 + 10010605101111.

It is an arithmetic number, because the mean of its divisors is an integer number (10010605101111).

Almost surely, 2^{20021210202221} is an apocalyptic number.

It is an amenable number.

20021210202221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20021210202221 is an equidigital number, since it uses as much as digits as its factorization.

20021210202221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 20021210202221 its reverse (12220201212002), we get a palindrome (32241411414223).

The spelling of 20021210202221 in words is "twenty trillion, twenty-one billion, two hundred ten million, two hundred two thousand, two hundred twenty-one".