131216765 has 4 divisors (see below), whose sum is σ = 157460124. Its totient is φ = 104973408.

The previous prime is 131216759. The next prime is 131216783. The reversal of 131216765 is 567612131.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 567612131 = 1789 ⋅317279.

It can be written as a sum of positive squares in 2 ways, for example, as 92813956 + 38402809 = 9634^2 + 6197^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-131216765 is a prime.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

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, 13121672 + ... + 13121681.

It is an arithmetic number, because the mean of its divisors is an integer number (39365031).

Almost surely, 2^131216765 is an apocalyptic number.

It is an amenable number.

131216765 is a deficient number, since it is larger than the sum of its proper divisors (26243359).

131216765 is an equidigital number, since it uses as much as digits as its factorization.

131216765 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 26243358.

The product of its digits is 7560, while the sum is 32.

The square root of 131216765 is about 11454.9886512384. The cubic root of 131216765 is about 508.1552796334.

Adding to 131216765 its reverse (567612131), we get a palindrome (698828896).

The spelling of 131216765 in words is "one hundred thirty-one million, two hundred sixteen thousand, seven hundred sixty-five".