31919 has 4 divisors (see below), whose sum is σ = 32520.
Its totient is φ = 31320.
The previous prime is 31907. The next prime is 31957. The reversal of 31919 is 91913.
It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 91913 = 107 ⋅859.
It is a cyclic number.
It is not a de Polignac number, because 31919 - 28 = 31663 is a prime.
It is a super-2 number, since 2×319192 = 2037645122, which contains 22 as substring.
It is a Duffinian number.
It is a junction number, because it is equal to n+sod(n) for n = 31894 and 31903.
It is a congruent number.
It is not an unprimeable number, because it can be changed into a prime (31019) 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 3 ways as a sum of consecutive naturals, for example, 212 + ... + 329.
It is an arithmetic number, because the mean of its divisors is an integer number (8130).
231919 is an apocalyptic number.
31919 is a deficient number, since it is larger than the sum of its proper divisors (601).
31919 is an equidigital number, since it uses as much as digits as its factorization.
31919 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 600.
The product of its digits is 243, while the sum is 23.
The square root of 31919 is about 178.6588928657.
The cubic root of 31919 is about 31.7212110129.
The spelling of 31919 in words is "thirty-one thousand, nine hundred nineteen".