31331313281 has 2 divisors, whose sum is σ = 31331313282. Its totient is φ = 31331313280.

The previous prime is 31331313257. The next prime is 31331313341. The reversal of 31331313281 is 18231313313.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 28731945025 + 2599368256 = 169505^2 + 50984^2 .

It is a cyclic number.

It is not a de Polignac number, because 31331313281 - 2⁶ = 31331313217 is a prime.

It is a super-2 number, since 2×31331313281² (a number of 22 digits) contains 22 as substring.

It is not a weakly prime, because it can be changed into another prime (31331313781) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15665656640 + 15665656641.

It is an arithmetic number, because the mean of its divisors is an integer number (15665656641).

Almost surely, 2^31331313281 is an apocalyptic number.

It is an amenable number.

31331313281 is a deficient number, since it is larger than the sum of its proper divisors (1).

31331313281 is an equidigital number, since it uses as much as digits as its factorization.

31331313281 is an evil number, because the sum of its binary digits is even.

The product of its digits is 3888, while the sum is 29.

Adding to 31331313281 its reverse (18231313313), we get a palindrome (49562626594).

The spelling of 31331313281 in words is "thirty-one billion, three hundred thirty-one million, three hundred thirteen thousand, two hundred eighty-one".