31131 has 8 divisors (see below), whose sum is σ = 46160. Its totient is φ = 20736.

The previous prime is 31123. The next prime is 31139. The reversal of 31131 is 13113.

It is an interprime number because it is at equal distance from previous prime (31123) and next prime (31139).

It is not a de Polignac number, because 31131 - 2³ = 31123 is a prime.

It is a super-2 number, since 2×31131² = 1938278322, which contains 22 as substring.

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a nude number because it is divisible by every one of its digits and also a Zuckerman number because it is divisible by the product of its digits.

It is a Duffinian number.

It is a plaindrome in base 13 and base 16.

It is not an unprimeable number, because it can be changed into a prime (31139) by changing a digit.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 550 + ... + 603.

It is an arithmetic number, because the mean of its divisors is an integer number (5770).

2³¹¹³¹ is an apocalyptic number.

31131 is a deficient number, since it is larger than the sum of its proper divisors (15029).

31131 is a wasteful number, since it uses less digits than its factorization.

31131 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 1162 (or 1156 counting only the distinct ones).

The product of its digits is 9, while the sum is 9.

The square root of 31131 is about 176.4397914304. The cubic root of 31131 is about 31.4579938952.

Adding to 31131 its reverse (13113), we get a palindrome (44244).

The spelling of 31131 in words is "thirty-one thousand, one hundred thirty-one".