201210821221 has 2 divisors, whose sum is σ = 201210821222. Its totient is φ = 201210821220.

The previous prime is 201210821213. The next prime is 201210821297. The reversal of 201210821221 is 122128012102.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 181467480100 + 19743341121 = 425990^2 + 140511^2 .

It is a cyclic number.

It is not a de Polignac number, because 201210821221 - 2³ = 201210821213 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 201210821192 and 201210821201.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (201210831221) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 100605410610 + 100605410611.

It is an arithmetic number, because the mean of its divisors is an integer number (100605410611).

Almost surely, 2^201210821221 is an apocalyptic number.

It is an amenable number.

201210821221 is a deficient number, since it is larger than the sum of its proper divisors (1).

201210821221 is an equidigital number, since it uses as much as digits as its factorization.

201210821221 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 256, while the sum is 22.

Adding to 201210821221 its reverse (122128012102), we get a palindrome (323338833323).

The spelling of 201210821221 in words is "two hundred one billion, two hundred ten million, eight hundred twenty-one thousand, two hundred twenty-one".