21112012121021 has 8 divisors (see below), whose sum is σ = 21495299816184. Its totient is φ = 20729924075520.

The previous prime is 21112012121009. The next prime is 21112012121027. The reversal of 21112012121021 is 12012121021112.

It can be written as a sum of positive squares in 4 ways, for example, as 91575232996 + 21020436888025 = 302614^2 + 4584805^2 .

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 21112012121021 - 2¹⁸ = 21112011858877 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 (21112012121027) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 299876900 + ... + 299947293.

It is an arithmetic number, because the mean of its divisors is an integer number (2686912477023).

Almost surely, 2^{21112012121021} is an apocalyptic number.

It is an amenable number.

21112012121021 is a deficient number, since it is larger than the sum of its proper divisors (383287695163).

21112012121021 is an equidigital number, since it uses as much as digits as its factorization.

21112012121021 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 599824831.

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

Adding to 21112012121021 its reverse (12012121021112), we get a palindrome (33124133142133).

The spelling of 21112012121021 in words is "twenty-one trillion, one hundred twelve billion, twelve million, one hundred twenty-one thousand, twenty-one".