21221031211 has 2 divisors, whose sum is σ = 21221031212. Its totient is φ = 21221031210.

The previous prime is 21221031151. The next prime is 21221031233. The reversal of 21221031211 is 11213012212.

It is a strong prime.

It is a cyclic number.

It is not a de Polignac number, because 21221031211 - 2²¹ = 21218934059 is a prime.

It is a super-2 number, since 2×21221031211² (a number of 21 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (21221031511) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10610515605 + 10610515606.

It is an arithmetic number, because the mean of its divisors is an integer number (10610515606).

Almost surely, 2^21221031211 is an apocalyptic number.

21221031211 is a deficient number, since it is larger than the sum of its proper divisors (1).

21221031211 is an equidigital number, since it uses as much as digits as its factorization.

21221031211 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 48, while the sum is 16.

Adding to 21221031211 its reverse (11213012212), we get a palindrome (32434043423).

The spelling of 21221031211 in words is "twenty-one billion, two hundred twenty-one million, thirty-one thousand, two hundred eleven".