131531240 has 64 divisors (see below), whose sum is σ = 308610000. Its totient is φ = 50391040.

The previous prime is 131531221. The next prime is 131531249. The reversal of 131531240 is 42135131.

It can be written as a sum of positive squares in 8 ways, for example, as 2617924 + 128913316 = 1618^2 + 11354^2 .

It is a Harshad number since it is a multiple of its sum of digits (20).

It is not an unprimeable number, because it can be changed into a prime (131531249) by changing a digit.

It is a polite number, since it can be written in 15 ways as a sum of consecutive naturals, for example, 172460 + ... + 173220.

Almost surely, 2^131531240 is an apocalyptic number.

131531240 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 131531240, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (154305000).

131531240 is an abundant number, since it is smaller than the sum of its proper divisors (177078760).

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

131531240 is a wasteful number, since it uses less digits than its factorization.

131531240 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 950 (or 946 counting only the distinct ones).

The product of its (nonzero) digits is 360, while the sum is 20.

The square root of 131531240 is about 11468.7069890202. The cubic root of 131531240 is about 508.5609052415.

Adding to 131531240 its reverse (42135131), we get a palindrome (173666371).

The spelling of 131531240 in words is "one hundred thirty-one million, five hundred thirty-one thousand, two hundred forty".