21010220022221 has 2 divisors, whose sum is σ = 21010220022222. Its totient is φ = 21010220022220.

The previous prime is 21010220022217. The next prime is 21010220022263. The reversal of 21010220022221 is 12222002201012.

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., 20948288224900 + 61931797321 = 4576930^2 + 248861^2 .

It is a cyclic number.

It is not a de Polignac number, because 21010220022221 - 2² = 21010220022217 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21010220022221.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21010220024221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10505110011110 + 10505110011111.

It is an arithmetic number, because the mean of its divisors is an integer number (10505110011111).

Almost surely, 2^{21010220022221} is an apocalyptic number.

It is an amenable number.

21010220022221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21010220022221 is an equidigital number, since it uses as much as digits as its factorization.

21010220022221 is an evil number, because the sum of its binary digits is even.

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

Adding to 21010220022221 its reverse (12222002201012), we get a palindrome (33232222223233).

The spelling of 21010220022221 in words is "twenty-one trillion, ten billion, two hundred twenty million, twenty-two thousand, two hundred twenty-one".