21121210112 has 72 divisors (see below), whose sum is σ = 42617400000. Its totient is φ = 10446630912.

The previous prime is 21121210087. The next prime is 21121210151. The reversal of 21121210112 is 21101212112.

It is a super-2 number, since 2×21121210112² (a number of 21 digits) contains 22 as substring.

It is a congruent number.

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, 10564889 + ... + 10566887.

Almost surely, 2^21121210112 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 21121210112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (21308700000).

21121210112 is an abundant number, since it is smaller than the sum of its proper divisors (21496189888).

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

21121210112 is a wasteful number, since it uses less digits than its factorization.

21121210112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2441 (or 2427 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 14.

Adding to 21121210112 its reverse (21101212112), we get a palindrome (42222422224).

The spelling of 21121210112 in words is "twenty-one billion, one hundred twenty-one million, two hundred ten thousand, one hundred twelve".