21031120231 has 12 divisors (see below), whose sum is σ = 23442450192. Its totient is φ = 18849908000.

The previous prime is 21031120211. The next prime is 21031120249. The reversal of 21031120231 is 13202113012.

It is a de Polignac number, because none of the positive numbers 2^k-21031120231 is a prime.

It is a super-2 number, since 2×21031120231² (a number of 21 digits) contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (21031120211) 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, 1215430 + ... + 1232611.

It is an arithmetic number, because the mean of its divisors is an integer number (1953537516).

Almost surely, 2^21031120231 is an apocalyptic number.

21031120231 is a deficient number, since it is larger than the sum of its proper divisors (2411329961).

21031120231 is a wasteful number, since it uses less digits than its factorization.

21031120231 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2448134 (or 2448123 counting only the distinct ones).

The product of its (nonzero) digits is 72, while the sum is 16.

Adding to 21031120231 its reverse (13202113012), we get a palindrome (34233233243).

The spelling of 21031120231 in words is "twenty-one billion, thirty-one million, one hundred twenty thousand, two hundred thirty-one".