21120120120 has 128 divisors (see below), whose sum is σ = 69192506880. Its totient is φ = 5114688000.

The previous prime is 21120120101. The next prime is 21120120137. The reversal of 21120120120 is 2102102112.

It is a super-3 number, since 3×21120120120³ (a number of 32 digits) contains 333 as substring.

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

21120120120 is a modest number, since divided by 120120 gives 21120 as remainder.

It is a junction number, because it is equal to n+sod(n) for n = 21120120096 and 21120120105.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 1339885 + ... + 1355555.

It is an arithmetic number, because the mean of its divisors is an integer number (540566460).

Almost surely, 2^21120120120 is an apocalyptic number.

21120120120 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 21120120120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34596253440).

21120120120 is an abundant number, since it is smaller than the sum of its proper divisors (48072386760).

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

21120120120 is a wasteful number, since it uses less digits than its factorization.

21120120120 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 16717 (or 16713 counting only the distinct ones).

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

Adding to 21120120120 its reverse (2102102112), we get a palindrome (23222222232).

The spelling of 21120120120 in words is "twenty-one billion, one hundred twenty million, one hundred twenty thousand, one hundred twenty".