21121012120220 has 96 divisors (see below), whose sum is σ = 48515256115200. Its totient is φ = 7689049297920.

The previous prime is 21121012120217. The next prime is 21121012120249. The reversal of 21121012120220 is 2202121012112.

It is a Harshad number since it is a multiple of its sum of digits (17).

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, 13009181 + ... + 14542379.

It is an arithmetic number, because the mean of its divisors is an integer number (505367251200).

Almost surely, 2^{21121012120220} is an apocalyptic number.

21121012120220 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 21121012120220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24257628057600).

21121012120220 is an abundant number, since it is smaller than the sum of its proper divisors (27394243994980).

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

21121012120220 is a wasteful number, since it uses less digits than its factorization.

21121012120220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1534563 (or 1534561 counting only the distinct ones).

The product of its (nonzero) digits is 64, while the sum is 17.

Adding to 21121012120220 its reverse (2202121012112), we get a palindrome (23323133132332).

The spelling of 21121012120220 in words is "twenty-one trillion, one hundred twenty-one billion, twelve million, one hundred twenty thousand, two hundred twenty".