21202121112 has 64 divisors (see below), whose sum is σ = 54324293760. Its totient is φ = 6892032000.

The previous prime is 21202121111. The next prime is 21202121173. The reversal of 21202121112 is 21112120212.

It is a super-2 number, since 2×21202121112² (a number of 21 digits) contains 22 as substring.

It is a junction number, because it is equal to n+sod(n) for n = 21202121091 and 21202121100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21202121111) 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, 645487 + ... + 677537.

It is an arithmetic number, because the mean of its divisors is an integer number (848817090).

Almost surely, 2^21202121112 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 21202121112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (27162146880).

21202121112 is an abundant number, since it is smaller than the sum of its proper divisors (33122172648).

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

21202121112 is a wasteful number, since it uses less digits than its factorization.

21202121112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 32744 (or 32740 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21202121112 its reverse (21112120212), we get a palindrome (42314241324).

The spelling of 21202121112 in words is "twenty-one billion, two hundred two million, one hundred twenty-one thousand, one hundred twelve".