31145 has 4 divisors (see below), whose sum is σ = 37380.
Its totient is φ = 24912.
The previous prime is 31139. The next prime is 31147. The reversal of 31145 is 54113.
Adding to 31145 its reverse (54113), we get a palindrome (85258).
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 54113 = 53 ⋅1021.
It can be written as a sum of positive squares in 2 ways, for example, as 13456 + 17689 = 116^2 + 133^2
It is a cyclic number.
It is not a de Polignac number, because 31145 - 26 = 31081 is a prime.
It is a super-2 number, since 2×311452 = 1940022050, which contains 22 as substring.
It is a plaindrome in base 13.
It is not an unprimeable number, because it can be changed into a prime (31147) by changing a digit.
It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 3110 + ... + 3119.
It is an arithmetic number, because the mean of its divisors is an integer number (9345).
231145 is an apocalyptic number.
It is an amenable number.
31145 is a deficient number, since it is larger than the sum of its proper divisors (6235).
31145 is an equidigital number, since it uses as much as digits as its factorization.
31145 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 6234.
The product of its digits is 60, while the sum is 14.
The square root of 31145 is about 176.4794605613.
The cubic root of 31145 is about 31.4627088729.
The spelling of 31145 in words is "thirty-one thousand, one hundred forty-five".