21211221212112 has 80 divisors (see below), whose sum is σ = 57649219088832. Its totient is φ = 6711526794240.

The previous prime is 21211221212089. The next prime is 21211221212113. The reversal of 21211221212112 is 21121212211212.

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

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21211221212113) 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, 145576638 + ... + 145722269.

Almost surely, 2^{21211221212112} is an apocalyptic number.

It is an amenable number.

21211221212112 is an abundant number, since it is smaller than the sum of its proper divisors (36437997876720).

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

21211221212112 is a wasteful number, since it uses less digits than its factorization.

21211221212112 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 291298996 (or 291298990 counting only the distinct ones).

The product of its digits is 128, while the sum is 21.

Adding to 21211221212112 its reverse (21121212211212), we get a palindrome (42332433423324).

The spelling of 21211221212112 in words is "twenty-one trillion, two hundred eleven billion, two hundred twenty-one million, two hundred twelve thousand, one hundred twelve".