21001110220220 has 144 divisors (see below), whose sum is σ = 48351018949632. Its totient is φ = 7657682123520.

The previous prime is 21001110220151. The next prime is 21001110220267. The reversal of 21001110220220 is 2202201110012.

It is a junction number, because it is equal to n+sod(n) for n = 21001110220195 and 21001110220204.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 47 ways as a sum of consecutive naturals, for example, 747063965 + ... + 747092075.

It is an arithmetic number, because the mean of its divisors is an integer number (335770964928).

Almost surely, 2^{21001110220220} is an apocalyptic number.

21001110220220 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 21001110220220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (24175509474816).

21001110220220 is an abundant number, since it is smaller than the sum of its proper divisors (27349908729412).

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

21001110220220 is a wasteful number, since it uses less digits than its factorization.

21001110220220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 30892 (or 30877 counting only the distinct ones).

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

Adding to 21001110220220 its reverse (2202201110012), we get a palindrome (23203311330232).

The spelling of 21001110220220 in words is "twenty-one trillion, one billion, one hundred ten million, two hundred twenty thousand, two hundred twenty".