1311565 has 4 divisors (see below), whose sum is σ = 1573884. Its totient is φ = 1049248.

The previous prime is 1311559. The next prime is 1311577. The reversal of 1311565 is 5651131.

It is a semiprime because it is the product of two primes.

It can be written as a sum of positive squares in 2 ways, for example, as 1022121 + 289444 = 1011^2 + 538^2 .

It is a cyclic number.

It is not a de Polignac number, because 1311565 - 2⁹ = 1311053 is a prime.

It is a Smith number, since the sum of its digits (22) coincides with the sum of the digits of its prime factors. Since it is squarefree, it is also a hoax number.

It is a Duffinian number.

It is a congruent number.

It is an unprimeable number.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131152 + ... + 131161.

It is an arithmetic number, because the mean of its divisors is an integer number (393471).

2^1311565 is an apocalyptic number.

It is an amenable number.

1311565 is a deficient number, since it is larger than the sum of its proper divisors (262319).

1311565 is an equidigital number, since it uses as much as digits as its factorization.

1311565 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 262318.

The product of its digits is 450, while the sum is 22.

The square root of 1311565 is about 1145.2357835835. The cubic root of 1311565 is about 109.4619732709.

Adding to 1311565 its reverse (5651131), we get a palindrome (6962696).

The spelling of 1311565 in words is "one million, three hundred eleven thousand, five hundred sixty-five".