21031131313 has 6 divisors (see below), whose sum is σ = 21488125106. Its totient is φ = 20583658272.

The previous prime is 21031131287. The next prime is 21031131349. The reversal of 21031131313 is 31313113012.

It can be written as a sum of positive squares in only one way, i.e., 14465594529 + 6565536784 = 120273^2 + 81028^2 .

It is not a de Polignac number, because 21031131313 - 2³³ = 12441196721 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (21031131353) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 4758120 + ... + 4762537.

Almost surely, 2^21031131313 is an apocalyptic number.

It is an amenable number.

21031131313 is a deficient number, since it is larger than the sum of its proper divisors (456993793).

21031131313 is an frugal number, since it uses more digits than its factorization.

21031131313 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 9520751 (or 9520704 counting only the distinct ones).

The product of its (nonzero) digits is 162, while the sum is 19.

Adding to 21031131313 its reverse (31313113012), we get a palindrome (52344244325).

The spelling of 21031131313 in words is "twenty-one billion, thirty-one million, one hundred thirty-one thousand, three hundred thirteen".