131531 has 4 divisors (see below), whose sum is σ = 132912.
Its totient is φ = 130152.
The previous prime is 131519. The next prime is 131543. The reversal of 131531 is 135131.
Adding to 131531 its reverse (135131), we get a palindrome (266662).
Subtracting 131531 from its reverse (135131), we obtain a square (3600 = 602).
It is a semiprime because it is the product of two primes.
It is an interprime number because it is at equal distance from previous prime (131519) and next prime (131543).
It is a cyclic number.
It is a de Polignac number, because none of the positive numbers 2k-131531 is a prime.
It is a super-2 number, since 2×1315312 = 34600807922, which contains 22 as substring.
It is a Duffinian number.
It is not an unprimeable number, because it can be changed into a prime (131501) by changing a digit.
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, 536 + ... + 741.
It is an arithmetic number, because the mean of its divisors is an integer number (33228).
2131531 is an apocalyptic number.
131531 is a deficient number, since it is larger than the sum of its proper divisors (1381).
131531 is a wasteful number, since it uses less digits than its factorization.
131531 is an odious number, because the sum of its binary digits is odd.
The sum of its prime factors is 1380.
The product of its digits is 45, while the sum is 14.
The square root of 131531 is about 362.6720281466.
The cubic root of 131531 is about 50.8560595924.
The spelling of 131531 in words is "one hundred thirty-one thousand, five hundred thirty-one".