131228665 has 4 divisors (see below), whose sum is σ = 157474404. Its totient is φ = 104982928.

The previous prime is 131228663. The next prime is 131228701. The reversal of 131228665 is 566822131.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 566822131 = 1181 ⋅479951.

It can be written as a sum of positive squares in 2 ways, for example, as 67420521 + 63808144 = 8211^2 + 7988^2 .

It is a cyclic number.

It is not a de Polignac number, because 131228665 - 2¹ = 131228663 is a prime.

It is a Duffinian number.

It is a self number, because there is not a number n which added to its sum of digits gives 131228665.

It is not an unprimeable number, because it can be changed into a prime (131228663) 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, 13122862 + ... + 13122871.

It is an arithmetic number, because the mean of its divisors is an integer number (39368601).

Almost surely, 2^131228665 is an apocalyptic number.

It is an amenable number.

131228665 is a deficient number, since it is larger than the sum of its proper divisors (26245739).

131228665 is an equidigital number, since it uses as much as digits as its factorization.

131228665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26245738.

The product of its digits is 17280, while the sum is 34.

The square root of 131228665 is about 11455.5080638093. The cubic root of 131228665 is about 508.1706406406.

The spelling of 131228665 in words is "one hundred thirty-one million, two hundred twenty-eight thousand, six hundred sixty-five".