201220100000021 has 2 divisors, whose sum is σ = 201220100000022. Its totient is φ = 201220100000020.

The previous prime is 201220099999939. The next prime is 201220100000111. The reversal of 201220100000021 is 120000001022102.

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., 154105260799396 + 47114839200625 = 12413914^2 + 6864025^2 .

It is a cyclic number.

It is not a de Polignac number, because 201220100000021 - 2³⁴ = 201202920130837 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 201220099999948 and 201220100000011.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201220100006021) 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, 100610050000010 + 100610050000011.

It is an arithmetic number, because the mean of its divisors is an integer number (100610050000011).

Almost surely, 2^{201220100000021} is an apocalyptic number.

It is an amenable number.

201220100000021 is a deficient number, since it is larger than the sum of its proper divisors (1).

201220100000021 is an equidigital number, since it uses as much as digits as its factorization.

201220100000021 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 11.

Adding to 201220100000021 its reverse (120000001022102), we get a palindrome (321220101022123).

The spelling of 201220100000021 in words is "two hundred one trillion, two hundred twenty billion, one hundred million, twenty-one", and thus it is an aban number.