31724 has 24 divisors (see below), whose sum is σ = 69888. Its totient is φ = 12240.

The previous prime is 31723. The next prime is 31727. The reversal of 31724 is 42713.

It is a happy number.

It is a Smith number, since the sum of its digits (17) coincides with the sum of the digits of its prime factors.

It is not an unprimeable number, because it can be changed into a 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 in 7 ways as a sum of consecutive naturals, for example, 257 + ... + 359.

It is an arithmetic number, because the mean of its divisors is an integer number (2912).

2³¹⁷²⁴ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31724, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (34944).

31724 is an abundant number, since it is smaller than the sum of its proper divisors (38164).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31724 is a wasteful number, since it uses less digits than its factorization.

31724 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 125 (or 123 counting only the distinct ones).

The product of its digits is 168, while the sum is 17.

The square root of 31724 is about 178.1123241104. The cubic root of 31724 is about 31.6564817969.

The spelling of 31724 in words is "thirty-one thousand, seven hundred twenty-four".