21121021212 has 24 divisors (see below), whose sum is σ = 49976502912. Its totient is φ = 6941180400.

The previous prime is 21121021211. The next prime is 21121021231. The reversal of 21121021212 is 21212012112.

It is a junction number, because it is equal to n+sod(n) for n = 21121021191 and 21121021200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21121021211) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 12394114 + ... + 12395817.

It is an arithmetic number, because the mean of its divisors is an integer number (2082354288).

Almost surely, 2^21121021212 is an apocalyptic number.

It is an amenable number.

21121021212 is an abundant number, since it is smaller than the sum of its proper divisors (28855481700).

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

21121021212 is a wasteful number, since it uses less digits than its factorization.

21121021212 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 24790009 (or 24790007 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 15.

Adding to 21121021212 its reverse (21212012112), we get a palindrome (42333033324).

The spelling of 21121021212 in words is "twenty-one billion, one hundred twenty-one million, twenty-one thousand, two hundred twelve".