21220121111020 has 96 divisors (see below), whose sum is σ = 48477010236480. Its totient is φ = 7755666969600.

The previous prime is 21220121111011. The next prime is 21220121111023. The reversal of 21220121111020 is 2011112102212.

It is a junction number, because it is equal to n+sod(n) for n = 21220121110985 and 21220121111003.

It is not an unprimeable number, because it can be changed into a prime (21220121111023) by changing a digit.

It is a polite number, since it can be written in 31 ways as a sum of consecutive naturals, for example, 110695174 + ... + 110886706.

It is an arithmetic number, because the mean of its divisors is an integer number (504968856630).

Almost surely, 2^{21220121111020} is an apocalyptic number.

21220121111020 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 21220121111020, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24238505118240).

21220121111020 is an abundant number, since it is smaller than the sum of its proper divisors (27256889125460).

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

21220121111020 is a wasteful number, since it uses less digits than its factorization.

21220121111020 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 195875 (or 195873 counting only the distinct ones).

The product of its (nonzero) digits is 32, while the sum is 16.

Adding to 21220121111020 its reverse (2011112102212), we get a palindrome (23231233213232).

The spelling of 21220121111020 in words is "twenty-one trillion, two hundred twenty billion, one hundred twenty-one million, one hundred eleven thousand, twenty".