21100222020221 has 4 divisors (see below), whose sum is σ = 21100243080444. Its totient is φ = 21100200960000.

The previous prime is 21100222020193. The next prime is 21100222020233. The reversal of 21100222020221 is 12202022200112.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 20208351436900 + 891870583321 = 4495370^2 + 944389^2 .

It is a cyclic number.

It is not a de Polignac number, because 21100222020221 - 2¹⁴ = 21100222003837 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 21100222020221.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21100222020271) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 8948030 + ... + 11057471.

It is an arithmetic number, because the mean of its divisors is an integer number (5275060770111).

Almost surely, 2^{21100222020221} is an apocalyptic number.

It is an amenable number.

21100222020221 is a deficient number, since it is larger than the sum of its proper divisors (21060223).

21100222020221 is a wasteful number, since it uses less digits than its factorization.

21100222020221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 21060222.

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

Adding to 21100222020221 its reverse (12202022200112), we get a palindrome (33302244220333).

The spelling of 21100222020221 in words is "twenty-one trillion, one hundred billion, two hundred twenty-two million, twenty thousand, two hundred twenty-one".