21344410221 has 4 divisors (see below), whose sum is σ = 28459213632. Its totient is φ = 14229606812.

The previous prime is 21344410181. The next prime is 21344410237. The reversal of 21344410221 is 12201444312.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 21344410221 - 2¹⁰ = 21344409197 is a prime.

It is a junction number, because it is equal to n+sod(n) for n = 21344410191 and 21344410200.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21344410271) 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, 3557401701 + ... + 3557401706.

It is an arithmetic number, because the mean of its divisors is an integer number (7114803408).

Almost surely, 2^21344410221 is an apocalyptic number.

It is an amenable number.

21344410221 is a deficient number, since it is larger than the sum of its proper divisors (7114803411).

21344410221 is an equidigital number, since it uses as much as digits as its factorization.

21344410221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 7114803410.

The product of its (nonzero) digits is 1536, while the sum is 24.

Adding to 21344410221 its reverse (12201444312), we get a palindrome (33545854533).

The spelling of 21344410221 in words is "twenty-one billion, three hundred forty-four million, four hundred ten thousand, two hundred twenty-one".