21100221320 has 32 divisors (see below), whose sum is σ = 47520005400. Its totient is φ = 8432176128.

The previous prime is 21100221301. The next prime is 21100221323. The reversal of 21100221320 is 2312200112.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 18446529124 + 2653692196 = 135818^2 + 51514^2 .

It is a junction number, because it is equal to n+sod(n) for n = 21100221295 and 21100221304.

It is not an unprimeable number, because it can be changed into a prime (21100221323) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 203969 + ... + 289488.

Almost surely, 2^21100221320 is an apocalyptic number.

21100221320 is a gapful number since it is divisible by the number (20) formed by its first and last digit.

It is an amenable number.

21100221320 is an abundant number, since it is smaller than the sum of its proper divisors (26419784080).

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

21100221320 is a wasteful number, since it uses less digits than its factorization.

21100221320 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 494537 (or 494533 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 14.

Adding to 21100221320 its reverse (2312200112), we get a palindrome (23412421432).

The spelling of 21100221320 in words is "twenty-one billion, one hundred million, two hundred twenty-one thousand, three hundred twenty".