20001221120120 has 128 divisors (see below), whose sum is σ = 46328642841600. Its totient is φ = 7768246886400.

The previous prime is 20001221120117. The next prime is 20001221120129. The reversal of 20001221120120 is 2102112210002.

It is a junction number, because it is equal to n+sod(n) for n = 20001221120095 and 20001221120104.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (20001221120129) by changing a digit.

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, 1035303821 + ... + 1035323139.

It is an arithmetic number, because the mean of its divisors is an integer number (361942522200).

Almost surely, 2^{20001221120120} is an apocalyptic number.

20001221120120 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 20001221120120, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (23164321420800).

20001221120120 is an abundant number, since it is smaller than the sum of its proper divisors (26327421721480).

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

20001221120120 is a wasteful number, since it uses less digits than its factorization.

20001221120120 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 24909 (or 24905 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 14.

Adding to 20001221120120 its reverse (2102112210002), we get a palindrome (22103333330122).

The spelling of 20001221120120 in words is "twenty trillion, one billion, two hundred twenty-one million, one hundred twenty thousand, one hundred twenty".