21021002122112 has 128 divisors (see below), whose sum is σ = 43126150636800. Its totient is φ = 10200033423360.

The previous prime is 21021002122111. The next prime is 21021002122139. The reversal of 21021002122112 is 21122120012012.

It is a tau number, because it is divible by the number of its divisors (128).

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021002122111) 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, 810388439 + ... + 810414377.

It is an arithmetic number, because the mean of its divisors is an integer number (336923051850).

Almost surely, 2^{21021002122112} is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21021002122112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21563075318400).

21021002122112 is an abundant number, since it is smaller than the sum of its proper divisors (22105148514688).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

21021002122112 is a wasteful number, since it uses less digits than its factorization.

21021002122112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 26804 (or 26792 counting only the distinct ones).

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

Adding to 21021002122112 its reverse (21122120012012), we get a palindrome (42143122134124).

The spelling of 21021002122112 in words is "twenty-one trillion, twenty-one billion, two million, one hundred twenty-two thousand, one hundred twelve".