131665 has 8 divisors (see below), whose sum is σ = 167400. Its totient is φ = 99072.

The previous prime is 131641. The next prime is 131671. The reversal of 131665 is 566131.

It can be written as a sum of positive squares in 4 ways, for example, as 18769 + 112896 = 137^2 + 336^2 .

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

It is a cyclic number.

It is not a de Polignac number, because 131665 - 2¹⁵ = 98897 is a prime.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (5) of ones.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 690 + ... + 859.

It is an arithmetic number, because the mean of its divisors is an integer number (20925).

2¹³¹⁶⁶⁵ is an apocalyptic number.

It is an amenable number.

131665 is a deficient number, since it is larger than the sum of its proper divisors (35735).

131665 is a wasteful number, since it uses less digits than its factorization.

131665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 1571.

The product of its digits is 540, while the sum is 22.

The square root of 131665 is about 362.8567210346. The cubic root of 131665 is about 50.8733239612.

Adding to 131665 its reverse (566131), we get a palindrome (697796).

The spelling of 131665 in words is "one hundred thirty-one thousand, six hundred sixty-five".