31281 has 4 divisors (see below), whose sum is σ = 41712. Its totient is φ = 20852.

The previous prime is 31277. The next prime is 31307. The reversal of 31281 is 18213.

It is a happy number.

31281 is digitally balanced in base 4, because in such base it contains all the possibile digits an equal number of times.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is not a de Polignac number, because 31281 - 2² = 31277 is a prime.

It is a super-2 number, since 2×31281² = 1957001922, which contains 22 as substring.

It is a D-number.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 31281.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 31281.

It is not an unprimeable number, because it can be changed into a prime (31231) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 5211 + ... + 5216.

It is an arithmetic number, because the mean of its divisors is an integer number (10428).

2³¹²⁸¹ is an apocalyptic number.

It is an amenable number.

31281 is a deficient number, since it is larger than the sum of its proper divisors (10431).

31281 is a wasteful number, since it uses less digits than its factorization.

31281 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 10430.

The product of its digits is 48, while the sum is 15.

The square root of 31281 is about 176.8643548033. The cubic root of 31281 is about 31.5084381526.

Adding to 31281 its product of digits (48), we get a square (31329 = 177²).

Adding to 31281 its reverse (18213), we get a palindrome (49494).

It can be divided in two parts, 312 and 81, that added together give a palindrome (393).

The spelling of 31281 in words is "thirty-one thousand, two hundred eighty-one".