131205820 has 24 divisors (see below), whose sum is σ = 279309744. Its totient is φ = 51762816.

The previous prime is 131205791. The next prime is 131205821. The reversal of 131205820 is 28502131.

It is a junction number, because it is equal to n+sod(n) for n = 131205791 and 131205800.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131205821) 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, 43474 + ... + 46393.

It is an arithmetic number, because the mean of its divisors is an integer number (11637906).

Almost surely, 2^131205820 is an apocalyptic number.

131205820 is a gapful number since it is divisible by the number (10) formed by its first and last digit.

It is an amenable number.

131205820 is an abundant number, since it is smaller than the sum of its proper divisors (148103924).

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

131205820 is a wasteful number, since it uses less digits than its factorization.

131205820 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 89949 (or 89947 counting only the distinct ones).

The product of its (nonzero) digits is 480, while the sum is 22.

The square root of 131205820 is about 11454.5109018238. The cubic root of 131205820 is about 508.1411505593.

Adding to 131205820 its reverse (28502131), we get a palindrome (159707951).

The spelling of 131205820 in words is "one hundred thirty-one million, two hundred five thousand, eight hundred twenty".