21021212120 has 32 divisors (see below), whose sum is σ = 47354176800. Its totient is φ = 8398449408.

The previous prime is 21021212117. The next prime is 21021212141. The reversal of 21021212120 is 2121212012.

It is a junction number, because it is equal to n+sod(n) for n = 21021212095 and 21021212104.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 279629 + ... + 346748.

It is an arithmetic number, because the mean of its divisors is an integer number (1479818025).

Almost surely, 2^21021212120 is an apocalyptic number.

21021212120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021212120 is an abundant number, since it is smaller than the sum of its proper divisors (26332964680).

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

21021212120 is a wasteful number, since it uses less digits than its factorization.

21021212120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 627227 (or 627223 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 21021212120 its reverse (2121212012), we get a palindrome (23142424132).

The spelling of 21021212120 in words is "twenty-one billion, twenty-one million, two hundred twelve thousand, one hundred twenty".