131161581 has 6 divisors (see below), whose sum is σ = 189455630. Its totient is φ = 87441048.

The previous prime is 131161573. The next prime is 131161607. The reversal of 131161581 is 185161131.

It is a happy number.

131161581 is a `hidden beast` number, since 13 + 11 + 61 + 581 = 666.

It can be written as a sum of positive squares in only one way, i.e., 91584900 + 39576681 = 9570^2 + 6291^2 .

It is not a de Polignac number, because 131161581 - 2³ = 131161573 is a prime.

It is a super-2 number, since 2×131161581² = 34406720660839122, which contains 22 as substring.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131161531) by changing a digit.

It is a polite number, since it can be written in 5 ways as a sum of consecutive naturals, for example, 7286746 + ... + 7286763.

Almost surely, 2^131161581 is an apocalyptic number.

It is an amenable number.

131161581 is a deficient number, since it is larger than the sum of its proper divisors (58294049).

131161581 is a wasteful number, since it uses less digits than its factorization.

131161581 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 14573515 (or 14573512 counting only the distinct ones).

The product of its digits is 720, while the sum is 27.

The square root of 131161581 is about 11452.5796657347. The cubic root of 131161581 is about 508.0840337247.

The spelling of 131161581 in words is "one hundred thirty-one million, one hundred sixty-one thousand, five hundred eighty-one".