1312660565 has 4 divisors (see below), whose sum is σ = 1575192684. Its totient is φ = 1050128448.

The previous prime is 1312660549. The next prime is 1312660579. The reversal of 1312660565 is 5650662131.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5650662131 = 829 ⋅6816239.

It can be written as a sum of positive squares in 2 ways, for example, as 717007729 + 595652836 = 26777^2 + 24406^2 .

It is a cyclic number.

It is not a de Polignac number, because 1312660565 - 2⁴ = 1312660549 is a prime.

It is a super-2 number, since 2×1312660565² = 3446155517812238450, which contains 22 as substring.

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, 131266052 + ... + 131266061.

It is an arithmetic number, because the mean of its divisors is an integer number (393798171).

Almost surely, 2^1312660565 is an apocalyptic number.

It is an amenable number.

1312660565 is a deficient number, since it is larger than the sum of its proper divisors (262532119).

1312660565 is an equidigital number, since it uses as much as digits as its factorization.

1312660565 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 262532118.

The product of its (nonzero) digits is 32400, while the sum is 35.

The square root of 1312660565 is about 36230.6578052345. The cubic root of 1312660565 is about 1094.9244306112.

The spelling of 1312660565 in words is "one billion, three hundred twelve million, six hundred sixty thousand, five hundred sixty-five".