131365661 has 4 divisors (see below), whose sum is σ = 150132192. Its totient is φ = 112599132.

The previous prime is 131365657. The next prime is 131365667. The reversal of 131365661 is 166563131.

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: 166563131 = 7 ⋅23794733.

It is a cyclic number.

It is not a de Polignac number, because 131365661 - 2² = 131365657 is a prime.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (131365667) 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, 9383255 + ... + 9383268.

It is an arithmetic number, because the mean of its divisors is an integer number (37533048).

Almost surely, 2^131365661 is an apocalyptic number.

It is an amenable number.

131365661 is a deficient number, since it is larger than the sum of its proper divisors (18766531).

131365661 is an equidigital number, since it uses as much as digits as its factorization.

131365661 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 18766530.

The product of its digits is 9720, while the sum is 32.

The square root of 131365661 is about 11461.4859856827. The cubic root of 131365661 is about 508.3474138415.

The spelling of 131365661 in words is "one hundred thirty-one million, three hundred sixty-five thousand, six hundred sixty-one".