21100221220220 has 48 divisors (see below), whose sum is σ = 46119629072160. Its totient is φ = 8099056740096.

The previous prime is 21100221220219. The next prime is 21100221220261. The reversal of 21100221220220 is 2202212200112.

It is a happy number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 111499607 + ... + 111688686.

It is an arithmetic number, because the mean of its divisors is an integer number (960825605670).

Almost surely, 2^{21100221220220} is an apocalyptic number.

21100221220220 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21100221220220 is an abundant number, since it is smaller than the sum of its proper divisors (25019407851940).

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

21100221220220 is a wasteful number, since it uses less digits than its factorization.

21100221220220 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 223188494 (or 223188492 counting only the distinct ones).

The product of its (nonzero) digits is 128, while the sum is 17.

Adding to 21100221220220 its reverse (2202212200112), we get a palindrome (23302433420332).

The spelling of 21100221220220 in words is "twenty-one trillion, one hundred billion, two hundred twenty-one million, two hundred twenty thousand, two hundred twenty".