201220120021 has 2 divisors, whose sum is σ = 201220120022. Its totient is φ = 201220120020.

The previous prime is 201220120009. The next prime is 201220120043. The reversal of 201220120021 is 120021022102.

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., 180162047025 + 21058072996 = 424455^2 + 145114^2 .

It is a cyclic number.

It is not a de Polignac number, because 201220120021 - 2²⁵ = 201186565589 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 201220119983 and 201220120010.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201220120061) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100610060010 + 100610060011.

It is an arithmetic number, because the mean of its divisors is an integer number (100610060011).

Almost surely, 2^201220120021 is an apocalyptic number.

It is an amenable number.

201220120021 is a deficient number, since it is larger than the sum of its proper divisors (1).

201220120021 is an equidigital number, since it uses as much as digits as its factorization.

201220120021 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 201220120021 its reverse (120021022102), we get a palindrome (321241142123).

The spelling of 201220120021 in words is "two hundred one billion, two hundred twenty million, one hundred twenty thousand, twenty-one".