21211212112112 has 320 divisors, whose sum is σ = 50631016550400. Its totient is φ = 8483355095040.

The previous prime is 21211212112099. The next prime is 21211212112157. The reversal of 21211212112112 is 21121121211212.

It is a happy number.

It is a nude number because it is divisible by every one of its digits.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 1599752939 + ... + 1599766197.

It is an arithmetic number, because the mean of its divisors is an integer number (158221926720).

Almost surely, 2^{21211212112112} is an apocalyptic number.

21211212112112 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 21211212112112, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25315508275200).

21211212112112 is an abundant number, since it is smaller than the sum of its proper divisors (29419804438288).

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

21211212112112 is a wasteful number, since it uses less digits than its factorization.

21211212112112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 13684 (or 13678 counting only the distinct ones).

The product of its digits is 64, while the sum is 20.

Adding to 21211212112112 its reverse (21121121211212), we get a palindrome (42332333323324).

The spelling of 21211212112112 in words is "twenty-one trillion, two hundred eleven billion, two hundred twelve million, one hundred twelve thousand, one hundred twelve".