21021212112 has 40 divisors (see below), whose sum is σ = 56665879104. Its totient is φ = 6702415104.

The previous prime is 21021212083. The next prime is 21021212117. The reversal of 21021212112 is 21121212012.

It is a junction number, because it is equal to n+sod(n) for n = 21021212091 and 21021212100.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21021212117) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (19) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 9519373 + ... + 9521580.

Almost surely, 2^21021212112 is an apocalyptic number.

It is an amenable number.

21021212112 is an abundant number, since it is smaller than the sum of its proper divisors (35644666992).

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

21021212112 is a wasteful number, since it uses less digits than its factorization.

21021212112 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 19040987 (or 19040981 counting only the distinct ones).

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

Adding to 21021212112 its reverse (21121212012), we get a palindrome (42142424124).

The spelling of 21021212112 in words is "twenty-one billion, twenty-one million, two hundred twelve thousand, one hundred twelve".