21010212102221 has 16 divisors (see below), whose sum is σ = 22830074595840. Its totient is φ = 19261791912960.

The previous prime is 21010212102199. The next prime is 21010212102251. The reversal of 21010212102221 is 12220121201012.

It is a cyclic number.

It is not a de Polignac number, because 21010212102221 - 2¹⁸ = 21010211840077 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21010212102221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010212102251) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 21258581 + ... + 22224933.

It is an arithmetic number, because the mean of its divisors is an integer number (1426879662240).

Almost surely, 2^{21010212102221} is an apocalyptic number.

It is an amenable number.

21010212102221 is a deficient number, since it is larger than the sum of its proper divisors (1819862493619).

21010212102221 is a wasteful number, since it uses less digits than its factorization.

21010212102221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1003316.

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21010212102221 its reverse (12220121201012), we get a palindrome (33230333303233).

The spelling of 21010212102221 in words is "twenty-one trillion, ten billion, two hundred twelve million, one hundred two thousand, two hundred twenty-one".