21021111112021 has 4 divisors (see below), whose sum is σ = 21160323768544. Its totient is φ = 20881898455500.

The previous prime is 21021111111997. The next prime is 21021111112049. The reversal of 21021111112021 is 12021111112012.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21021111112021 - 2¹³ = 21021111103829 is a prime.

It is a super-2 number, since 2×21021111112021² (a number of 27 digits) contains 22 as substring.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21021111111986 and 21021111112004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021111112061) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 69606328035 + ... + 69606328336.

It is an arithmetic number, because the mean of its divisors is an integer number (5290080942136).

Almost surely, 2^{21021111112021} is an apocalyptic number.

It is an amenable number.

21021111112021 is a deficient number, since it is larger than the sum of its proper divisors (139212656523).

21021111112021 is a wasteful number, since it uses less digits than its factorization.

21021111112021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 139212656522.

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

Adding to 21021111112021 its reverse (12021111112012), we get a palindrome (33042222224033).

Subtracting from 21021111112021 its reverse (12021111112012), we obtain a palindrome (9000000000009).

The spelling of 21021111112021 in words is "twenty-one trillion, twenty-one billion, one hundred eleven million, one hundred twelve thousand, twenty-one".