21212212120 has 64 divisors (see below), whose sum is σ = 52081885440. Its totient is φ = 7711228800.

The previous prime is 21212212061. The next prime is 21212212181. The reversal of 21212212120 is 2121221212.

It is a happy number.

It is a junction number, because it is equal to n+sod(n) for n = 21212212094 and 21212212103.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 2328775 + ... + 2337865.

It is an arithmetic number, because the mean of its divisors is an integer number (813779460).

Almost surely, 2^21212212120 is an apocalyptic number.

21212212120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212212120 is an abundant number, since it is smaller than the sum of its proper divisors (30869673320).

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

21212212120 is a wasteful number, since it uses less digits than its factorization.

21212212120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14416 (or 14412 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 16.

Adding to 21212212120 its reverse (2121221212), we get a palindrome (23333433332).

It can be divided in two parts, 21212 and 212120, that added together give a palindrome (233332).

The spelling of 21212212120 in words is "twenty-one billion, two hundred twelve million, two hundred twelve thousand, one hundred twenty".