20010221221 has 2 divisors, whose sum is σ = 20010221222. Its totient is φ = 20010221220.

The previous prime is 20010221213. The next prime is 20010221227. The reversal of 20010221221 is 12212201002.

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., 19707948225 + 302272996 = 140385^2 + 17386^2 .

It is a cyclic number.

It is not a de Polignac number, because 20010221221 - 2³ = 20010221213 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (20010221227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10005110610 + 10005110611.

It is an arithmetic number, because the mean of its divisors is an integer number (10005110611).

Almost surely, 2^20010221221 is an apocalyptic number.

It is an amenable number.

20010221221 is a deficient number, since it is larger than the sum of its proper divisors (1).

20010221221 is an equidigital number, since it uses as much as digits as its factorization.

20010221221 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 13.

Adding to 20010221221 its reverse (12212201002), we get a palindrome (32222422223).

The spelling of 20010221221 in words is "twenty billion, ten million, two hundred twenty-one thousand, two hundred twenty-one".