21331211171 has 2 divisors, whose sum is σ = 21331211172. Its totient is φ = 21331211170.

The previous prime is 21331211147. The next prime is 21331211173. The reversal of 21331211171 is 17111213312.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-21331211171 is a prime.

Together with 21331211173, it forms a pair of twin primes.

It is a Chen prime.

It is not a weakly prime, because it can be changed into another prime (21331211173) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 10665605585 + 10665605586.

It is an arithmetic number, because the mean of its divisors is an integer number (10665605586).

Almost surely, 2^21331211171 is an apocalyptic number.

21331211171 is a deficient number, since it is larger than the sum of its proper divisors (1).

21331211171 is an equidigital number, since it uses as much as digits as its factorization.

21331211171 is an evil number, because the sum of its binary digits is even.

The product of its digits is 252, while the sum is 23.

Adding to 21331211171 its reverse (17111213312), we get a palindrome (38442424483).

The spelling of 21331211171 in words is "twenty-one billion, three hundred thirty-one million, two hundred eleven thousand, one hundred seventy-one".