21215321112 has 64 divisors (see below), whose sum is σ = 55970899200. Its totient is φ = 6682642560.

The previous prime is 21215321111. The next prime is 21215321119. The reversal of 21215321112 is 21112351212.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21215321111) 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, 122437 + ... + 239627.

It is an arithmetic number, because the mean of its divisors is an integer number (874545300).

Almost surely, 2^21215321112 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 21215321112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27985449600).

21215321112 is an abundant number, since it is smaller than the sum of its proper divisors (34755578088).

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

21215321112 is a wasteful number, since it uses less digits than its factorization.

21215321112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 117616 (or 117612 counting only the distinct ones).

The product of its digits is 240, while the sum is 21.

Adding to 21215321112 its reverse (21112351212), we get a palindrome (42327672324).

The spelling of 21215321112 in words is "twenty-one billion, two hundred fifteen million, three hundred twenty-one thousand, one hundred twelve".