21000021120120 has 256 divisors, whose sum is σ = 75901538073600. Its totient is φ = 4540653711360.

The previous prime is 21000021120059. The next prime is 21000021120161. The reversal of 21000021120120 is 2102112000012.

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 = 21000021120096 and 21000021120105.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 63 ways as a sum of consecutive naturals, for example, 9833140 + ... + 11776700.

It is an arithmetic number, because the mean of its divisors is an integer number (296490383100).

Almost surely, 2^{21000021120120} is an apocalyptic number.

21000021120120 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 21000021120120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (37950769036800).

21000021120120 is an abundant number, since it is smaller than the sum of its proper divisors (54901516953480).

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

21000021120120 is a wasteful number, since it uses less digits than its factorization.

21000021120120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1944278 (or 1944274 counting only the distinct ones).

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

Adding to 21000021120120 its reverse (2102112000012), we get a palindrome (23102133120132).

The spelling of 21000021120120 in words is "twenty-one trillion, twenty-one million, one hundred twenty thousand, one hundred twenty".