21221220121112 has 96 divisors (see below), whose sum is σ = 44585963730000. Its totient is φ = 9459322414080.

The previous prime is 21221220121093. The next prime is 21221220121121. The reversal of 21221220121112 is 21112102212212.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 22904564 + ... + 23813052.

Almost surely, 2^{21221220121112} is an apocalyptic number.

21221220121112 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21221220121112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (22292981865000).

21221220121112 is an abundant number, since it is smaller than the sum of its proper divisors (23364743608888).

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

21221220121112 is a wasteful number, since it uses less digits than its factorization.

21221220121112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 908985 (or 908970 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 20.

Adding to 21221220121112 its reverse (21112102212212), we get a palindrome (42333322333324).

Subtracting from 21221220121112 its reverse (21112102212212), we obtain a square (109117908900 = 330330²).

The spelling of 21221220121112 in words is "twenty-one trillion, two hundred twenty-one billion, two hundred twenty million, one hundred twenty-one thousand, one hundred twelve".