21100221120320 has 112 divisors (see below), whose sum is σ = 51473727235728. Its totient is φ = 8233698263040.

The previous prime is 21100221120311. The next prime is 21100221120421. The reversal of 21100221120320 is 2302112200112.

It can be written as a sum of positive squares in 8 ways, for example, as 2143741079104 + 18956480041216 = 1464152^2 + 4353904^2 .

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, 246521372 + ... + 246606948.

It is an arithmetic number, because the mean of its divisors is an integer number (459586850319).

Almost surely, 2^{21100221120320} is an apocalyptic number.

21100221120320 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 21100221120320, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (25736863617864).

21100221120320 is an abundant number, since it is smaller than the sum of its proper divisors (30373506115408).

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

21100221120320 is a wasteful number, since it uses less digits than its factorization.

21100221120320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 104428 (or 104418 counting only the distinct ones).

The product of its (nonzero) digits is 96, while the sum is 17.

Adding to 21100221120320 its reverse (2302112200112), we get a palindrome (23402333320432).

The spelling of 21100221120320 in words is "twenty-one trillion, one hundred billion, two hundred twenty-one million, one hundred twenty thousand, three hundred twenty".