131231 has 2 divisors, whose sum is σ = 131232. Its totient is φ = 131230.

The previous prime is 131221. The next prime is 131249. The reversal of 131231 is 132131.

It is a m-pointer prime, because the next prime (131249) can be obtained adding 131231 to its product of digits (18).

It is a weak prime.

It is a cyclic number.

It is not a de Polignac number, because 131231 - 2¹⁴ = 114847 is a prime.

It is a super-2 number, since 2×131231² = 34443150722, which contains 22 as substring.

It is a Chen prime.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (131221) 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 as a sum of consecutive naturals, namely, 65615 + 65616.

It is an arithmetic number, because the mean of its divisors is an integer number (65616).

2¹³¹²³¹ is an apocalyptic number.

131231 is a deficient number, since it is larger than the sum of its proper divisors (1).

131231 is an equidigital number, since it uses as much as digits as its factorization.

131231 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 18, while the sum is 11.

The square root of 131231 is about 362.2581952144. The cubic root of 131231 is about 50.8173654645.

Adding to 131231 its reverse (132131), we get a palindrome (263362).

Subtracting 131231 from its reverse (132131), we obtain a square (900 = 30²).

The spelling of 131231 in words is "one hundred thirty-one thousand, two hundred thirty-one".