21021200120 has 64 divisors (see below), whose sum is σ = 47744640000. Its totient is φ = 8329335808.

The previous prime is 21021200089. The next prime is 21021200141. The reversal of 21021200120 is 2100212012.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

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 15 ways as a sum of consecutive naturals, for example, 2278076 + ... + 2287284.

It is an arithmetic number, because the mean of its divisors is an integer number (746010000).

Almost surely, 2^21021200120 is an apocalyptic number.

21021200120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21021200120 is an abundant number, since it is smaller than the sum of its proper divisors (26723439880).

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

21021200120 is a wasteful number, since it uses less digits than its factorization.

21021200120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9752 (or 9748 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 11.

Adding to 21021200120 its reverse (2100212012), we get a palindrome (23121412132).

The spelling of 21021200120 in words is "twenty-one billion, twenty-one million, two hundred thousand, one hundred twenty".