131161561 has 4 divisors (see below), whose sum is σ = 131645824. Its totient is φ = 130677300.

The previous prime is 131161549. The next prime is 131161573. The reversal of 131161561 is 165161131.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also an emirpimes, since its reverse is a distinct semiprime: 165161131 = 397 ⋅416023.

It is an interprime number because it is at equal distance from previous prime (131161549) and next prime (131161573).

It is a cyclic number.

It is not a de Polignac number, because 131161561 - 2²¹ = 129064409 is a prime.

It is a Duffinian number.

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

It is a pernicious number, because its binary representation contains a prime number (17) of ones.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 241725 + ... + 242266.

It is an arithmetic number, because the mean of its divisors is an integer number (32911456).

Almost surely, 2^131161561 is an apocalyptic number.

It is an amenable number.

131161561 is a deficient number, since it is larger than the sum of its proper divisors (484263).

131161561 is an equidigital number, since it uses as much as digits as its factorization.

131161561 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 484262.

The product of its digits is 540, while the sum is 25.

The square root of 131161561 is about 11452.5787925689. The cubic root of 131161561 is about 508.0840078999.

The spelling of 131161561 in words is "one hundred thirty-one million, one hundred sixty-one thousand, five hundred sixty-one".