21012000212221 has 2 divisors, whose sum is σ = 21012000212222. Its totient is φ = 21012000212220.

The previous prime is 21012000212197. The next prime is 21012000212293. The reversal of 21012000212221 is 12221200021012.

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., 20994998920900 + 17001291321 = 4582030^2 + 130389^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21012000212221 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21012000212195 and 21012000212204.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21012000212521) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10506000106110 + 10506000106111.

It is an arithmetic number, because the mean of its divisors is an integer number (10506000106111).

Almost surely, 2^{21012000212221} is an apocalyptic number.

It is an amenable number.

21012000212221 is a deficient number, since it is larger than the sum of its proper divisors (1).

21012000212221 is an equidigital number, since it uses as much as digits as its factorization.

21012000212221 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21012000212221 its reverse (12221200021012), we get a palindrome (33233200233233).

The spelling of 21012000212221 in words is "twenty-one trillion, twelve billion, two hundred twelve thousand, two hundred twenty-one".