31421 has 4 divisors (see below), whose sum is σ = 33852. Its totient is φ = 28992.

The previous prime is 31397. The next prime is 31469. The reversal of 31421 is 12413.

It is a happy number.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 19321 + 12100 = 139^2 + 110^2 .

It is a cyclic number.

It is not a de Polignac number, because 31421 - 2⁶ = 31357 is a prime.

It is a plaindrome in base 16.

It is a congruent number.

It is an inconsummate number, since it does not exist a number n which divided by its sum of digits gives 31421.

It is not an unprimeable number, because it can be changed into a prime (31481) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 1196 + ... + 1221.

It is an arithmetic number, because the mean of its divisors is an integer number (8463).

2³¹⁴²¹ is an apocalyptic number.

It is an amenable number.

31421 is a deficient number, since it is larger than the sum of its proper divisors (2431).

31421 is a wasteful number, since it uses less digits than its factorization.

31421 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 2430.

The product of its digits is 24, while the sum is 11.

The square root of 31421 is about 177.2596964908. The cubic root of 31421 is about 31.5553741715. Note that the first 3 decimals are identical.

Adding to 31421 its reverse (12413), we get a palindrome (43834).

The spelling of 31421 in words is "thirty-one thousand, four hundred twenty-one".