131820 has 48 divisors (see below), whose sum is σ = 399840. Its totient is φ = 32448.

The previous prime is 131797. The next prime is 131837. The reversal of 131820 is 28131.

It is a happy number.

It is a Harshad number since it is a multiple of its sum of digits (15).

It is a self number, because there is not a number n which added to its sum of digits gives 131820.

It is a Saint-Exupery number, since it is equal to the product of the sides of a Pythagorean triangle: 65 × 39 × 52.

It is an unprimeable number.

It is a pernicious number, because its binary representation contains a prime number (7) of ones.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 10134 + ... + 10146.

It is an arithmetic number, because the mean of its divisors is an integer number (8330).

2¹³¹⁸²⁰ is an apocalyptic number.

131820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

It is a practical number, because each smaller number is the sum of distinct divisors of 131820, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (199920).

131820 is an abundant number, since it is smaller than the sum of its proper divisors (268020).

It is a pseudoperfect number, because it is the sum of a subset of its proper divisors.

131820 is a wasteful number, since it uses less digits than its factorization.

131820 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 51 (or 23 counting only the distinct ones).

The product of its (nonzero) digits is 48, while the sum is 15.

The square root of 131820 is about 363.0702411380. The cubic root of 131820 is about 50.8932793352.

Adding to 131820 its reverse (28131), we get a palindrome (159951).

The spelling of 131820 in words is "one hundred thirty-one thousand, eight hundred twenty".