21331321111 has 2 divisors, whose sum is σ = 21331321112. Its totient is φ = 21331321110.

The previous prime is 21331321097. The next prime is 21331321139. The reversal of 21331321111 is 11112313312.

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 21331321111 - 2²¹ = 21329223959 is a prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (21331361111) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10665660555 + 10665660556.

It is an arithmetic number, because the mean of its divisors is an integer number (10665660556).

Almost surely, 2^21331321111 is an apocalyptic number.

21331321111 is a deficient number, since it is larger than the sum of its proper divisors (1).

21331321111 is an equidigital number, since it uses as much as digits as its factorization.

21331321111 is an evil number, because the sum of its binary digits is even.

The product of its digits is 108, while the sum is 19.

Adding to 21331321111 its reverse (11112313312), we get a palindrome (32443634423).

The spelling of 21331321111 in words is "twenty-one billion, three hundred thirty-one million, three hundred twenty-one thousand, one hundred eleven".