201221110021 has 2 divisors, whose sum is σ = 201221110022. Its totient is φ = 201221110020.

The previous prime is 201221109967. The next prime is 201221110031. The reversal of 201221110021 is 120011122102.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 198831269025 + 2389840996 = 445905^2 + 48886^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-201221110021 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 201221109983 and 201221110010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201221110031) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100610555010 + 100610555011.

It is an arithmetic number, because the mean of its divisors is an integer number (100610555011).

Almost surely, 2^201221110021 is an apocalyptic number.

It is an amenable number.

201221110021 is a deficient number, since it is larger than the sum of its proper divisors (1).

201221110021 is an equidigital number, since it uses as much as digits as its factorization.

201221110021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 201221110021 its reverse (120011122102), we get a palindrome (321232232123).

The spelling of 201221110021 in words is "two hundred one billion, two hundred twenty-one million, one hundred ten thousand, twenty-one".