31729 has 2 divisors, whose sum is σ = 31730. Its totient is φ = 31728.

The previous prime is 31727. The next prime is 31741. The reversal of 31729 is 92713.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 31329 + 400 = 177^2 + 20^2 .

It is a cyclic number.

It is not a de Polignac number, because 31729 - 2¹ = 31727 is a prime.

Together with 31727, it forms a pair of twin primes.

It is an Ulam number.

It is a plaindrome in base 13.

It is not a weakly prime, because it can be changed into another prime (31721) 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, 15864 + 15865.

It is an arithmetic number, because the mean of its divisors is an integer number (15865).

2³¹⁷²⁹ is an apocalyptic number.

It is an amenable number.

31729 is a deficient number, since it is larger than the sum of its proper divisors (1).

31729 is an equidigital number, since it uses as much as digits as its factorization.

31729 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 378, while the sum is 22.

The square root of 31729 is about 178.1263596439. The cubic root of 31729 is about 31.6581448291.

The spelling of 31729 in words is "thirty-one thousand, seven hundred twenty-nine".