21210000120 has 128 divisors (see below), whose sum is σ = 71859240000. Its totient is φ = 5563261440.

The previous prime is 21210000109. The next prime is 21210000167. The reversal of 21210000120 is 2100001212.

It is a Harshad number since it is a multiple of its sum of digits (9).

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 31 ways as a sum of consecutive naturals, for example, 95095 + ... + 226854.

Almost surely, 2^21210000120 is an apocalyptic number.

21210000120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21210000120 is an abundant number, since it is smaller than the sum of its proper divisors (50649239880).

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

21210000120 is a wasteful number, since it uses less digits than its factorization.

21210000120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 322030 (or 322020 counting only the distinct ones).

The product of its (nonzero) digits is 8, while the sum is 9.

Adding to 21210000120 its reverse (2100001212), we get a palindrome (23310001332).

The spelling of 21210000120 in words is "twenty-one billion, two hundred ten million, one hundred twenty", and thus it is an aban number.