210020021221 has 2 divisors, whose sum is σ = 210020021222. Its totient is φ = 210020021220.

The previous prime is 210020021153. The next prime is 210020021227. The reversal of 210020021221 is 122120020012.

It is a happy number.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 128232029025 + 81787992196 = 358095^2 + 285986^2 .

It is a cyclic number.

It is not a de Polignac number, because 210020021221 - 2⁹ = 210020020709 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (210020021227) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 105010010610 + 105010010611.

It is an arithmetic number, because the mean of its divisors is an integer number (105010010611).

Almost surely, 2^210020021221 is an apocalyptic number.

It is an amenable number.

210020021221 is a deficient number, since it is larger than the sum of its proper divisors (1).

210020021221 is an equidigital number, since it uses as much as digits as its factorization.

210020021221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 210020021221 its reverse (122120020012), we get a palindrome (332140041233).

The spelling of 210020021221 in words is "two hundred ten billion, twenty million, twenty-one thousand, two hundred twenty-one".