21112020122021 has 4 divisors (see below), whose sum is σ = 21682615260492. Its totient is φ = 20541424983552.

The previous prime is 21112020121961. The next prime is 21112020122041. The reversal of 21112020122021 is 12022102021112.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 14955344121796 + 6156676000225 = 3867214^2 + 2481265^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21112020122021 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 (21112020122041) 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, 285297569180 + ... + 285297569253.

It is an arithmetic number, because the mean of its divisors is an integer number (5420653815123).

Almost surely, 2^{21112020122021} is an apocalyptic number.

It is an amenable number.

21112020122021 is a deficient number, since it is larger than the sum of its proper divisors (570595138471).

21112020122021 is an equidigital number, since it uses as much as digits as its factorization.

21112020122021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 570595138470.

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

Adding to 21112020122021 its reverse (12022102021112), we get a palindrome (33134122143133).

The spelling of 21112020122021 in words is "twenty-one trillion, one hundred twelve billion, twenty million, one hundred twenty-two thousand, twenty-one".