31020313021 has 2 divisors, whose sum is σ = 31020313022. Its totient is φ = 31020313020.

The previous prime is 31020313019. The next prime is 31020313031. The reversal of 31020313021 is 12031302013.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28488713796 + 2531599225 = 168786^2 + 50315^2 .

It is an emirp because it is prime and its reverse (12031302013) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31020313021 - 2¹ = 31020313019 is a prime.

Together with 31020313019, it forms a pair of twin primes.

It is a junction number, because it is equal to n+sod(n) for n = 31020312986 and 31020313004.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (31020313001) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15510156510 + 15510156511.

It is an arithmetic number, because the mean of its divisors is an integer number (15510156511).

Almost surely, 2^31020313021 is an apocalyptic number.

It is an amenable number.

31020313021 is a deficient number, since it is larger than the sum of its proper divisors (1).

31020313021 is an equidigital number, since it uses as much as digits as its factorization.

31020313021 is an odious number, because the sum of its binary digits is odd.

The product of its (nonzero) digits is 108, while the sum is 16.

Adding to 31020313021 its reverse (12031302013), we get a palindrome (43051615034).

The spelling of 31020313021 in words is "thirty-one billion, twenty million, three hundred thirteen thousand, twenty-one".