31631 has 4 divisors (see below), whose sum is σ = 32352. Its totient is φ = 30912.

The previous prime is 31627. The next prime is 31643. The reversal of 31631 is 13613.

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

It is a cyclic number.

It is not a de Polignac number, because 31631 - 2² = 31627 is a prime.

It is a super-2 number, since 2×31631² = 2001040322, which contains 22 as substring.

It is a Duffinian number.

It is a nialpdrome in base 14.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (31601) 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, 290 + ... + 383.

It is an arithmetic number, because the mean of its divisors is an integer number (8088).

2³¹⁶³¹ is an apocalyptic number.

31631 is a deficient number, since it is larger than the sum of its proper divisors (721).

31631 is an equidigital number, since it uses as much as digits as its factorization.

31631 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 720.

The product of its digits is 54, while the sum is 14.

The square root of 31631 is about 177.8510612844. The cubic root of 31631 is about 31.6255174969.

The spelling of 31631 in words is "thirty-one thousand, six hundred thirty-one".