131220 has 54 divisors (see below), whose sum is σ = 413322. Its totient is φ = 34992.

The previous prime is 131213. The next prime is 131221. The reversal of 131220 is 22131.

It is a happy number.

It can be written as a sum of positive squares in only one way, i.e., 104976 + 26244 = 324^2 + 162^2 .

It is a tau number, because it is divible by the number of its divisors (54).

It is a Harshad number since it is a multiple of its sum of digits (9).

It is a nialpdrome in base 9.

It is a zygodrome in base 9.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131221) by changing a digit.

131220 is an untouchable number, because it is not equal to the sum of proper divisors of any number.

It is a polite number, since it can be written in 17 ways as a sum of consecutive naturals, for example, 26242 + ... + 26246.

2¹³¹²²⁰ is an apocalyptic number.

131220 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 131220, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (206661).

131220 is an abundant number, since it is smaller than the sum of its proper divisors (282102).

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

131220 is an frugal number, since it uses more digits than its factorization.

131220 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 33 (or 10 counting only the distinct ones).

The product of its (nonzero) digits is 12, while the sum is 9.

The square root of 131220 is about 362.2430123550. The cubic root of 131220 is about 50.8159455596.

Adding to 131220 its reverse (22131), we get a palindrome (153351).

It can be divided in two parts, 131 and 220, that added together give a triangular number (351 = T₂₆).

The spelling of 131220 in words is "one hundred thirty-one thousand, two hundred twenty".