21210111010221 has 16 divisors (see below), whose sum is σ = 32465102659584. Its totient is φ = 12065713371504.

The previous prime is 21210111010199. The next prime is 21210111010237. The reversal of 21210111010221 is 12201011101212.

It is a happy number.

It is not a de Polignac number, because 21210111010221 - 2⁶ = 21210111010157 is a prime.

It is a self number, because there is not a number n which added to its sum of digits gives 21210111010221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21210111010021) 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 15 ways as a sum of consecutive naturals, for example, 2264581161 + ... + 2264590526.

It is an arithmetic number, because the mean of its divisors is an integer number (2029068916224).

Almost surely, 2^{21210111010221} is an apocalyptic number.

21210111010221 is a gapful number since it is divisible by the number (21) formed by its first and last digit.

It is an amenable number.

21210111010221 is a deficient number, since it is larger than the sum of its proper divisors (11254991649363).

21210111010221 is a wasteful number, since it uses less digits than its factorization.

21210111010221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 4529171920.

The product of its (nonzero) digits is 16, while the sum is 15.

Adding to 21210111010221 its reverse (12201011101212), we get a palindrome (33411122111433).

Subtracting from 21210111010221 its reverse (12201011101212), we obtain a palindrome (9009099909009).

The spelling of 21210111010221 in words is "twenty-one trillion, two hundred ten billion, one hundred eleven million, ten thousand, two hundred twenty-one".