131631786 has 72 divisors (see below), whose sum is σ = 337673700. Its totient is φ = 36812160.

The previous prime is 131631781. The next prime is 131631793. The reversal of 131631786 is 687136131.

131631786 is a `hidden beast` number, since 13 + 1 + 631 + 7 + 8 + 6 = 666.

It can be written as a sum of positive squares in 2 ways, for example, as 129618225 + 2013561 = 11385^2 + 1419^2 .

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 131631786.

It is not an unprimeable number, because it can be changed into a prime (131631781) by changing a digit.

It is a polite number, since it can be written in 35 ways as a sum of consecutive naturals, for example, 25990 + ... + 30638.

Almost surely, 2^131631786 is an apocalyptic number.

It is a practical number, because each smaller number is the sum of distinct divisors of 131631786, and also a Zumkeller number, because its divisors can be partitioned in two sets with the same sum (168836850).

131631786 is an abundant number, since it is smaller than the sum of its proper divisors (206041914).

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

131631786 is a wasteful number, since it uses less digits than its factorization.

131631786 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 4692 (or 4678 counting only the distinct ones).

The product of its digits is 18144, while the sum is 36.

The square root of 131631786 is about 11473.0896449039. The cubic root of 131631786 is about 508.6904580914.

The spelling of 131631786 in words is "one hundred thirty-one million, six hundred thirty-one thousand, seven hundred eighty-six".