21121221210112 has 104 divisors (see below), whose sum is σ = 43339663129392. Its totient is φ = 10285842432000.

The previous prime is 21121221210109. The next prime is 21121221210137. The reversal of 21121221210112 is 21101212212112.

It is a happy number.

It is a super-2 number, since 2×21121221210112² (a number of 27 digits) contains 22 as substring.

It is a self number, because there is not a number n which added to its sum of digits gives 21121221210112.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 100824903 + ... + 101034169.

Almost surely, 2^{21121221210112} 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 21121221210112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21669831564696).

21121221210112 is an abundant number, since it is smaller than the sum of its proper divisors (22218441919280).

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

21121221210112 is an equidigital number, since it uses as much as digits as its factorization.

21121221210112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 209933 (or 209911 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 19.

Adding to 21121221210112 its reverse (21101212212112), we get a palindrome (42222433422224).

The spelling of 21121221210112 in words is "twenty-one trillion, one hundred twenty-one billion, two hundred twenty-one million, two hundred ten thousand, one hundred twelve".