21010202112221 has 16 divisors (see below), whose sum is σ = 24623834235264. Its totient is φ = 17551446522624.

The previous prime is 21010202112197. The next prime is 21010202112259. The reversal of 21010202112221 is 12221120201012.

It is a de Polignac number, because none of the positive numbers 2^k-21010202112221 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 21010202112221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21010202112281) 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, 76231520 + ... + 76506633.

It is an arithmetic number, because the mean of its divisors is an integer number (1538989639704).

Almost surely, 2^{21010202112221} is an apocalyptic number.

It is an amenable number.

21010202112221 is a deficient number, since it is larger than the sum of its proper divisors (3613632123043).

21010202112221 is a wasteful number, since it uses less digits than its factorization.

21010202112221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 152738660.

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

Adding to 21010202112221 its reverse (12221120201012), we get a palindrome (33231322313233).

The spelling of 21010202112221 in words is "twenty-one trillion, ten billion, two hundred two million, one hundred twelve thousand, two hundred twenty-one".