21210012120 has 256 divisors, whose sum is σ = 73160340480. Its totient is φ = 4868864000.

The previous prime is 21210012079. The next prime is 21210012169. The reversal of 21210012120 is 2121001212.

It is a super-2 number, since 2×21210012120² (a number of 21 digits) contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (12).

It is a junction number, because it is equal to n+sod(n) for n = 21210012096 and 21210012105.

It is a congruent number.

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 63 ways as a sum of consecutive naturals, for example, 3062902 + ... + 3069818.

It is an arithmetic number, because the mean of its divisors is an integer number (285782580).

Almost surely, 2^21210012120 is an apocalyptic number.

21210012120 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 21210012120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (36580170240).

21210012120 is an abundant number, since it is smaller than the sum of its proper divisors (51950328360).

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

21210012120 is a wasteful number, since it uses less digits than its factorization.

21210012120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7066 (or 7062 counting only the distinct ones).

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21210012120 its reverse (2121001212), we get a palindrome (23331013332).

The spelling of 21210012120 in words is "twenty-one billion, two hundred ten million, twelve thousand, one hundred twenty".