21211221111212 has 48 divisors (see below), whose sum is σ = 42022646860320. Its totient is φ = 9279633753600.

The previous prime is 21211221111203. The next prime is 21211221111217. The reversal of 21211221111212 is 21211112211212.

It is a happy number.

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

It is not an unprimeable number, because it can be changed into a prime (21211221111217) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 25815089 + ... + 26624072.

It is an arithmetic number, because the mean of its divisors is an integer number (875471809590).

Almost surely, 2^{21211221111212} is an apocalyptic number.

21211221111212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21211221111212 is a deficient number, since it is larger than the sum of its proper divisors (20811425749108).

21211221111212 is a wasteful number, since it uses less digits than its factorization.

21211221111212 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 52439522 (or 52439520 counting only the distinct ones).

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

Adding to 21211221111212 its reverse (21211112211212), we get a palindrome (42422333322424).

The spelling of 21211221111212 in words is "twenty-one trillion, two hundred eleven billion, two hundred twenty-one million, one hundred eleven thousand, two hundred twelve".