21221010211 has 4 divisors (see below), whose sum is σ = 21223268352. Its totient is φ = 21218752072.

The previous prime is 21221010179. The next prime is 21221010269. The reversal of 21221010211 is 11201012212.

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

It is a cyclic number.

It is not a de Polignac number, because 21221010211 - 2⁵ = 21221010179 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 21221010191 and 21221010200.

It is not an unprimeable number, because it can be changed into a prime (21221010311) 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, 1114915 + ... + 1133788.

It is an arithmetic number, because the mean of its divisors is an integer number (5305817088).

Almost surely, 2^21221010211 is an apocalyptic number.

21221010211 is a deficient number, since it is larger than the sum of its proper divisors (2258141).

21221010211 is an equidigital number, since it uses as much as digits as its factorization.

21221010211 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2258140.

The product of its (nonzero) digits is 16, while the sum is 13.

Adding to 21221010211 its reverse (11201012212), we get a palindrome (32422022423).

The spelling of 21221010211 in words is "twenty-one billion, two hundred twenty-one million, ten thousand, two hundred eleven".