21021211211021 has 12 divisors (see below), whose sum is σ = 25516430291232. Its totient is φ = 17234781861528.

The previous prime is 21021211210973. The next prime is 21021211211029. The reversal of 21021211211021 is 12011211212012.

It is not a de Polignac number, because 21021211211021 - 2¹⁰ = 21021211209997 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021211211029) 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 11 ways as a sum of consecutive naturals, for example, 9326179535 + ... + 9326181788.

It is an arithmetic number, because the mean of its divisors is an integer number (2126369190936).

Almost surely, 2^{21021211211021} is an apocalyptic number.

It is an amenable number.

21021211211021 is a deficient number, since it is larger than the sum of its proper divisors (4495219080211).

21021211211021 is a wasteful number, since it uses less digits than its factorization.

21021211211021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18652361360 (or 18652361353 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 17.

Adding to 21021211211021 its reverse (12011211212012), we get a palindrome (33032422423033).

Subtracting from 21021211211021 its reverse (12011211212012), we obtain a palindrome (9009999999009).

The spelling of 21021211211021 in words is "twenty-one trillion, twenty-one billion, two hundred eleven million, two hundred eleven thousand, twenty-one".