21121000112021 has 4 divisors (see below), whose sum is σ = 21247473166752. Its totient is φ = 20994527057292.

The previous prime is 21121000112011. The next prime is 21121000112099. The reversal of 21121000112021 is 12021100012112.

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 21121000112021 - 2⁶ = 21121000111957 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21121000111987 and 21121000112005.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121000112011) 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, 63236527115 + ... + 63236527448.

It is an arithmetic number, because the mean of its divisors is an integer number (5311868291688).

Almost surely, 2^{21121000112021} is an apocalyptic number.

It is an amenable number.

21121000112021 is a deficient number, since it is larger than the sum of its proper divisors (126473054731).

21121000112021 is a wasteful number, since it uses less digits than its factorization.

21121000112021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 126473054730.

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21121000112021 its reverse (12021100012112), we get a palindrome (33142100124133).

Subtracting from 21121000112021 its reverse (12021100012112), we obtain a palindrome (9099900099909).

The spelling of 21121000112021 in words is "twenty-one trillion, one hundred twenty-one billion, one hundred twelve thousand, twenty-one".