21112142112421 has 4 divisors (see below), whose sum is σ = 21122002993644. Its totient is φ = 21102281231200.

The previous prime is 21112142112361. The next prime is 21112142112493. The reversal of 21112142112421 is 12421124121112.

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 15163352820225 + 5948789292196 = 3894015^2 + 2439014^2 .

It is a cyclic number.

It is not a de Polignac number, because 21112142112421 - 2¹⁷ = 21112141981349 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 (21112142112521) 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, 4930437400 + ... + 4930441681.

It is an arithmetic number, because the mean of its divisors is an integer number (5280500748411).

Almost surely, 2^{21112142112421} is an apocalyptic number.

It is an amenable number.

21112142112421 is a deficient number, since it is larger than the sum of its proper divisors (9860881223).

21112142112421 is an equidigital number, since it uses as much as digits as its factorization.

21112142112421 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 9860881222.

The product of its digits is 512, while the sum is 25.

Adding to 21112142112421 its reverse (12421124121112), we get a palindrome (33533266233533).

The spelling of 21112142112421 in words is "twenty-one trillion, one hundred twelve billion, one hundred forty-two million, one hundred twelve thousand, four hundred twenty-one".