31665 has 8 divisors (see below), whose sum is σ = 50688. Its totient is φ = 16880.

The previous prime is 31663. The next prime is 31667. The reversal of 31665 is 56613.

31665 is nontrivially palindromic in base 14.

It is an interprime number because it is at equal distance from previous prime (31663) and next prime (31667).

It is a sphenic number, since it is the product of 3 distinct primes.

It is not a de Polignac number, because 31665 - 2¹ = 31663 is a prime.

It is a Curzon number.

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 31665.

It is not an unprimeable number, because it can be changed into a prime (31663) 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, 1041 + ... + 1070.

It is an arithmetic number, because the mean of its divisors is an integer number (6336).

2³¹⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

31665 is a deficient number, since it is larger than the sum of its proper divisors (19023).

31665 is a wasteful number, since it uses less digits than its factorization.

31665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 2119.

The product of its digits is 540, while the sum is 21.

The square root of 31665 is about 177.9466212098. The cubic root of 31665 is about 31.6368448083.

Subtracting from 31665 its product of digits (540), we obtain a triangular number (31125 = T₂₄₉).

It can be divided in two parts, 31 and 665, that added together give a palindrome (696).

The spelling of 31665 in words is "thirty-one thousand, six hundred sixty-five".