31513 has 2 divisors, whose sum is σ = 31514.
Its totient is φ = 31512.
The previous prime is 31511. The next prime is 31517.
31513 is nontrivially palindromic in base 10.
It is a weak prime.
It can be written as a sum of positive squares in only one way, i.e., 16384 + 15129 = 128^2 + 123^2
It is a palprime.
It is a cyclic number.
It is not a de Polignac number, because 31513 - 21 = 31511 is a prime.
Together with 31511, it forms a pair of twin primes.
It is a nialpdrome in base 8.
It is a junction number, because it is equal to n+sod(n) for n = 31493 and 31502.
It is not a weakly prime, because it can be changed into another prime (31511) by changing a digit.
It is a polite number, since it can be written as a sum of consecutive naturals, namely, 15756 + 15757.
It is an arithmetic number, because the mean of its divisors is an integer number (15757).
231513 is an apocalyptic number.
It is an amenable number.
31513 is a deficient number, since it is larger than the sum of its proper divisors (1).
31513 is an equidigital number, since it uses as much as digits as its factorization.
31513 is an odious number, because the sum of its binary digits is odd.
The product of its digits is 45, while the sum is 13.
The square root of 31513 is about 177.5190130662.
The cubic root of 31513 is about 31.5861419767.
It can be divided in two parts, 3151 and 3, that multiplied together give a triangular number (9453 = T137).
The spelling of 31513 in words is "thirty-one thousand, five hundred thirteen".