131805 has 24 divisors (see below), whose sum is σ = 238680. Its totient is φ = 67200.

The previous prime is 131797. The next prime is 131837. The reversal of 131805 is 508131.

It is a happy number.

It can be written as a sum of positive squares in 4 ways, for example, as 45369 + 86436 = 213^2 + 294^2 .

It is not a de Polignac number, because 131805 - 2³ = 131797 is a prime.

It is a Curzon number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 23 ways as a sum of consecutive naturals, for example, 1255 + ... + 1355.

It is an arithmetic number, because the mean of its divisors is an integer number (9945).

2¹³¹⁸⁰⁵ is an apocalyptic number.

131805 is a gapful number since it is divisible by the number (15) formed by its first and last digit.

It is an amenable number.

131805 is a deficient number, since it is larger than the sum of its proper divisors (106875).

131805 is a wasteful number, since it uses less digits than its factorization.

131805 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 141 (or 138 counting only the distinct ones).

The product of its (nonzero) digits is 120, while the sum is 18.

The square root of 131805 is about 363.0495833905. The cubic root of 131805 is about 50.8913488539.

Adding to 131805 its reverse (508131), we get a palindrome (639936).

The spelling of 131805 in words is "one hundred thirty-one thousand, eight hundred five".