31687 has 2 divisors, whose sum is σ = 31688. Its totient is φ = 31686.

The previous prime is 31667. The next prime is 31699. The reversal of 31687 is 78613.

It is a strong prime.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-31687 is a prime.

It is a plaindrome in base 13.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 31687.

It is not a weakly prime, because it can be changed into another prime (31607) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15843 + 15844.

It is an arithmetic number, because the mean of its divisors is an integer number (15844).

2³¹⁶⁸⁷ is an apocalyptic number.

31687 is a deficient number, since it is larger than the sum of its proper divisors (1).

31687 is an equidigital number, since it uses as much as digits as its factorization.

31687 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 1008, while the sum is 25.

The square root of 31687 is about 178.0084267668. The cubic root of 31687 is about 31.6441699249.

The spelling of 31687 in words is "thirty-one thousand, six hundred eighty-seven".