21031231311 has 12 divisors (see below), whose sum is σ = 31503573192. Its totient is φ = 14020820712.

The previous prime is 21031231297. The next prime is 21031231343. The reversal of 21031231311 is 11313213012.

21031231311 is a `hidden beast` number, since 2 + 10 + 312 + 31 + 311 = 666.

It is a de Polignac number, because none of the positive numbers 2^k-21031231311 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21031231511) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 43273896 + ... + 43274381.

It is an arithmetic number, because the mean of its divisors is an integer number (2625297766).

Almost surely, 2^21031231311 is an apocalyptic number.

21031231311 is a deficient number, since it is larger than the sum of its proper divisors (10472341881).

21031231311 is an frugal number, since it uses more digits than its factorization.

21031231311 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 86548292 (or 86548280 counting only the distinct ones).

The product of its (nonzero) digits is 108, while the sum is 18.

Adding to 21031231311 its reverse (11313213012), we get a palindrome (32344444323).

The spelling of 21031231311 in words is "twenty-one billion, thirty-one million, two hundred thirty-one thousand, three hundred eleven".