31321331513 has 2 divisors, whose sum is σ = 31321331514. Its totient is φ = 31321331512.

The previous prime is 31321331407. The next prime is 31321331533. The reversal of 31321331513 is 31513312313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 19613442304 + 11707889209 = 140048^2 + 108203^2 .

It is a cyclic number.

It is not a de Polignac number, because 31321331513 - 2⁸ = 31321331257 is a prime.

It is not a weakly prime, because it can be changed into another prime (31321331533) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15660665756 + 15660665757.

It is an arithmetic number, because the mean of its divisors is an integer number (15660665757).

Almost surely, 2^31321331513 is an apocalyptic number.

It is an amenable number.

31321331513 is a deficient number, since it is larger than the sum of its proper divisors (1).

31321331513 is an equidigital number, since it uses as much as digits as its factorization.

31321331513 is an evil number, because the sum of its binary digits is even.

The product of its digits is 2430, while the sum is 26.

Adding to 31321331513 its reverse (31513312313), we get a palindrome (62834643826).

The spelling of 31321331513 in words is "thirty-one billion, three hundred twenty-one million, three hundred thirty-one thousand, five hundred thirteen".