21101221111212 has 72 divisors (see below), whose sum is σ = 59760870313872. Its totient is φ = 6221490249600.

The previous prime is 21101221111207. The next prime is 21101221111273. The reversal of 21101221111212 is 21211112210112.

It is a happy number.

21101221111212 is a `hidden beast` number, since 21 + 101 + 221 + 111 + 212 = 666.

It is a Harshad number since it is a multiple of its sum of digits (18).

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, 720065239 + ... + 720094542.

Almost surely, 2^{21101221111212} is an apocalyptic number.

21101221111212 is a gapful number since it is divisible by the number (22) formed by its first and last digit.

It is an amenable number.

21101221111212 is an abundant number, since it is smaller than the sum of its proper divisors (38659649202660).

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

21101221111212 is a wasteful number, since it uses less digits than its factorization.

21101221111212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1440159839 (or 1440159834 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 18.

Adding to 21101221111212 its reverse (21211112210112), we get a palindrome (42312333321324).

The spelling of 21101221111212 in words is "twenty-one trillion, one hundred one billion, two hundred twenty-one million, one hundred eleven thousand, two hundred twelve".