21212002120 has 16 divisors (see below), whose sum is σ = 47727004860. Its totient is φ = 8484800832.

The previous prime is 21212002069. The next prime is 21212002139. The reversal of 21212002120 is 2120021212.

It is a happy number.

It can be written as a sum of positive squares in 2 ways, for example, as 21182473764 + 29528356 = 145542^2 + 5434^2 .

It is a self number, because there is not a number n which added to its sum of digits gives 21212002120.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 265149987 + ... + 265150066.

Almost surely, 2^21212002120 is an apocalyptic number.

21212002120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21212002120 is an abundant number, since it is smaller than the sum of its proper divisors (26515002740).

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

21212002120 is a wasteful number, since it uses less digits than its factorization.

21212002120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 530300064 (or 530300060 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 13.

Adding to 21212002120 its reverse (2120021212), we get a palindrome (23332023332).

The spelling of 21212002120 in words is "twenty-one billion, two hundred twelve million, two thousand, one hundred twenty".