31140 has 36 divisors (see below), whose sum is σ = 95004. Its totient is φ = 8256.

The previous prime is 31139. The next prime is 31147. The reversal of 31140 is 4113.

It can be written as a sum of positive squares in 2 ways, for example, as 20736 + 10404 = 144^2 + 102^2 .

It is a tau number, because it is divible by the number of its divisors (36).

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

It is a plaindrome in base 13.

It is not an unprimeable number, because it can be changed into a prime (31147) by changing a digit.

It is a polite number, since it can be written in 11 ways as a sum of consecutive naturals, for example, 94 + ... + 266.

It is an arithmetic number, because the mean of its divisors is an integer number (2639).

2³¹¹⁴⁰ is an apocalyptic number.

31140 is a gapful number since it is divisible by the number (30) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31140, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (47502).

31140 is an abundant number, since it is smaller than the sum of its proper divisors (63864).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

31140 is a wasteful number, since it uses less digits than its factorization.

31140 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 188 (or 183 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 31140 is about 176.4652940382. The cubic root of 31140 is about 31.4610251146.

Multiplying 31140 by its product of nonzero digits (12), we get a triangular number (373680 = T₈₆₄).

Adding to 31140 its reverse (4113), we get a palindrome (35253).

It can be divided in two parts, 311 and 40, that added together give a triangular number (351 = T₂₆).

The spelling of 31140 in words is "thirty-one thousand, one hundred forty".