31105 has 4 divisors (see below), whose sum is σ = 37332. Its totient is φ = 24880.

The previous prime is 31091. The next prime is 31121. The reversal of 31105 is 50113.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 50113 = 7 ⋅7159.

It can be written as a sum of positive squares in 2 ways, for example, as 5184 + 25921 = 72^2 + 161^2 .

It is not a de Polignac number, because 31105 - 2⁷ = 30977 is a prime.

It is a Duffinian number.

It is a junction number, because it is equal to n+sod(n) for n = 31091 and 31100.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3106 + ... + 3115.

It is an arithmetic number, because the mean of its divisors is an integer number (9333).

2³¹¹⁰⁵ is an apocalyptic number.

It is an amenable number.

31105 is a deficient number, since it is larger than the sum of its proper divisors (6227).

31105 is an equidigital number, since it uses as much as digits as its factorization.

31105 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 6226.

The product of its (nonzero) digits is 15, while the sum is 10.

The square root of 31105 is about 176.3660965152. The cubic root of 31105 is about 31.4492337564.

Adding to 31105 its reverse (50113), we get a palindrome (81218).

It can be divided in two parts, 31 and 105, that added together give a triangular number (136 = T₁₆).

The spelling of 31105 in words is "thirty-one thousand, one hundred five".