31351303681 has 2 divisors, whose sum is σ = 31351303682. Its totient is φ = 31351303680.

The previous prime is 31351303639. The next prime is 31351303691. The reversal of 31351303681 is 18630315313.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 29783856400 + 1567447281 = 172580^2 + 39591^2 .

It is an emirp because it is prime and its reverse (18630315313) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 31351303681 - 2⁷ = 31351303553 is a prime.

It is a super-2 number, since 2×31351303681² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31351303631) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15675651840 + 15675651841.

It is an arithmetic number, because the mean of its divisors is an integer number (15675651841).

Almost surely, 2^31351303681 is an apocalyptic number.

It is an amenable number.

31351303681 is a deficient number, since it is larger than the sum of its proper divisors (1).

31351303681 is an equidigital number, since it uses as much as digits as its factorization.

31351303681 is an evil number, because the sum of its binary digits is even.

The product of its (nonzero) digits is 19440, while the sum is 34.

Adding to 31351303681 its reverse (18630315313), we get a palindrome (49981618994).

The spelling of 31351303681 in words is "thirty-one billion, three hundred fifty-one million, three hundred three thousand, six hundred eighty-one".