31240 has 32 divisors (see below), whose sum is σ = 77760. Its totient is φ = 11200.

The previous prime is 31237. The next prime is 31247. The reversal of 31240 is 4213.

It is a Harshad number since it is a multiple of its sum of digits (10).

It is not an unprimeable number, because it can be changed into a prime (31247) 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, 405 + ... + 475.

It is an arithmetic number, because the mean of its divisors is an integer number (2430).

2³¹²⁴⁰ is an apocalyptic number.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 31240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (38880).

31240 is an abundant number, since it is smaller than the sum of its proper divisors (46520).

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

31240 is a wasteful number, since it uses less digits than its factorization.

31240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 93 (or 89 counting only the distinct ones).

The product of its (nonzero) digits is 24, while the sum is 10.

The square root of 31240 is about 176.7484087623. The cubic root of 31240 is about 31.4946660995.

Adding to 31240 its reverse (4213), we get a palindrome (35453).

The spelling of 31240 in words is "thirty-one thousand, two hundred forty".