31945 has 4 divisors (see below), whose sum is σ = 38340. Its totient is φ = 25552.

The previous prime is 31907. The next prime is 31957. The reversal of 31945 is 54913.

31945 is digitally balanced in base 6, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54913 = 89 ⋅617.

It can be written as a sum of positive squares in 2 ways, for example, as 3721 + 28224 = 61^2 + 168^2 .

It is a cyclic number.

It is not a de Polignac number, because 31945 - 2⁷ = 31817 is a prime.

31945 is strictly pandigital in base 6.

31945 is a lucky number.

It is a nialpdrome in base 8.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3190 + ... + 3199.

It is an arithmetic number, because the mean of its divisors is an integer number (9585).

2³¹⁹⁴⁵ is an apocalyptic number.

It is an amenable number.

31945 is a deficient number, since it is larger than the sum of its proper divisors (6395).

31945 is an equidigital number, since it uses as much as digits as its factorization.

31945 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6394.

The product of its digits is 540, while the sum is 22.

The square root of 31945 is about 178.7316424140. The cubic root of 31945 is about 31.7298216383.

The spelling of 31945 in words is "thirty-one thousand, nine hundred forty-five".