21201010221 has 4 divisors (see below), whose sum is σ = 28268013632. Its totient is φ = 14134006812.

The previous prime is 21201010213. The next prime is 21201010279. The reversal of 21201010221 is 12201010212.

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 not a de Polignac number, because 21201010221 - 2³ = 21201010213 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21201010197 and 21201010206.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21201018221) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (23) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3533501701 + ... + 3533501706.

It is an arithmetic number, because the mean of its divisors is an integer number (7067003408).

Almost surely, 2^21201010221 is an apocalyptic number.

It is an amenable number.

21201010221 is a deficient number, since it is larger than the sum of its proper divisors (7067003411).

21201010221 is an equidigital number, since it uses as much as digits as its factorization.

21201010221 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 7067003410.

The product of its (nonzero) digits is 16, while the sum is 12.

Adding to 21201010221 its reverse (12201010212), we get a palindrome (33402020433).

Subtracting from 21201010221 its reverse (12201010212), we obtain a palindrome (9000000009).

The spelling of 21201010221 in words is "twenty-one billion, two hundred one million, ten thousand, two hundred twenty-one".