21010212101221 has 32 divisors (see below), whose sum is σ = 24276589608960. Its totient is φ = 17811197789184.

The previous prime is 21010212101201. The next prime is 21010212101227. The reversal of 21010212101221 is 12210121201012.

It is a cyclic number.

It is not a de Polignac number, because 21010212101221 - 2¹⁵ = 21010212068453 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21010212101195 and 21010212101204.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010212101227) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1485548476 + ... + 1485562618.

It is an arithmetic number, because the mean of its divisors is an integer number (758643425280).

Almost surely, 2^{21010212101221} is an apocalyptic number.

It is an amenable number.

21010212101221 is a deficient number, since it is larger than the sum of its proper divisors (3266377507739).

21010212101221 is a wasteful number, since it uses less digits than its factorization.

21010212101221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 20665.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21010212101221 its reverse (12210121201012), we get a palindrome (33220333302233).

The spelling of 21010212101221 in words is "twenty-one trillion, ten billion, two hundred twelve million, one hundred one thousand, two hundred twenty-one".