31000313021 has 2 divisors, whose sum is σ = 31000313022. Its totient is φ = 31000313020.

The previous prime is 31000312997. The next prime is 31000313087. The reversal of 31000313021 is 12031300013.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 29656284100 + 1344028921 = 172210^2 + 36661^2 .

It is a cyclic number.

It is not a de Polignac number, because 31000313021 - 2¹⁰ = 31000311997 is a prime.

It is a super-2 number, since 2×31000313021² (a number of 22 digits) contains 22 as substring.

It is a Sophie Germain prime.

It is a Curzon number.

It is a junction number, because it is equal to n+sod(n) for n = 31000312987 and 31000313005.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31000313321) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15500156510 + 15500156511.

It is an arithmetic number, because the mean of its divisors is an integer number (15500156511).

Almost surely, 2^31000313021 is an apocalyptic number.

It is an amenable number.

31000313021 is a deficient number, since it is larger than the sum of its proper divisors (1).

31000313021 is an equidigital number, since it uses as much as digits as its factorization.

31000313021 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 54, while the sum is 14.

Adding to 31000313021 its reverse (12031300013), we get a palindrome (43031613034).

The spelling of 31000313021 in words is "thirty-one billion, three hundred thirteen thousand, twenty-one".