21201341221 has 4 divisors (see below), whose sum is σ = 21694395712. Its totient is φ = 20708286732.

The previous prime is 21201341191. The next prime is 21201341267. The reversal of 21201341221 is 12214310212.

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 a de Polignac number, because none of the positive numbers 2^k-21201341221 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201344221) 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, 246527181 + ... + 246527266.

It is an arithmetic number, because the mean of its divisors is an integer number (5423598928).

Almost surely, 2^21201341221 is an apocalyptic number.

It is an amenable number.

21201341221 is a deficient number, since it is larger than the sum of its proper divisors (493054491).

21201341221 is an equidigital number, since it uses as much as digits as its factorization.

21201341221 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 493054490.

The product of its (nonzero) digits is 192, while the sum is 19.

Adding to 21201341221 its reverse (12214310212), we get a palindrome (33415651433).

The spelling of 21201341221 in words is "twenty-one billion, two hundred one million, three hundred forty-one thousand, two hundred twenty-one".