21012112210021 has 16 divisors (see below), whose sum is σ = 22489670568960. Its totient is φ = 19587776866560.

The previous prime is 21012112209997. The next prime is 21012112210031. The reversal of 21012112210021 is 12001221121012.

It is a cyclic number.

It is not a de Polignac number, because 21012112210021 - 2¹⁵ = 21012112177253 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21012112209977 and 21012112210004.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21012112210031) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 26600065 + ... + 27378598.

It is an arithmetic number, because the mean of its divisors is an integer number (1405604410560).

Almost surely, 2^{21012112210021} is an apocalyptic number.

It is an amenable number.

21012112210021 is a deficient number, since it is larger than the sum of its proper divisors (1477558358939).

21012112210021 is a wasteful number, since it uses less digits than its factorization.

21012112210021 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 53979156.

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21012112210021 its reverse (12001221121012), we get a palindrome (33013333331033).

The spelling of 21012112210021 in words is "twenty-one trillion, twelve billion, one hundred twelve million, two hundred ten thousand, twenty-one".