21115125120 has 128 divisors (see below), whose sum is σ = 67442400000. Its totient is φ = 5619161088.

The previous prime is 21115125067. The next prime is 21115125131. The reversal of 21115125120 is 2152151112.

It is a tau number, because it is divible by the number of its divisors (128).

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 15 ways as a sum of consecutive naturals, for example, 947061 + ... + 969099.

It is an arithmetic number, because the mean of its divisors is an integer number (526893750).

Almost surely, 2^21115125120 is an apocalyptic number.

21115125120 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 21115125120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (33721200000).

21115125120 is an abundant number, since it is smaller than the sum of its proper divisors (46327274880).

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

21115125120 is a wasteful number, since it uses less digits than its factorization.

21115125120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 22560 (or 22548 counting only the distinct ones).

The product of its (nonzero) digits is 200, while the sum is 21.

Adding to 21115125120 its reverse (2152151112), we get a palindrome (23267276232).

The spelling of 21115125120 in words is "twenty-one billion, one hundred fifteen million, one hundred twenty-five thousand, one hundred twenty".