1311665 has 8 divisors (see below), whose sum is σ = 1656960. Its totient is φ = 994032.

The previous prime is 1311643. The next prime is 1311689. The reversal of 1311665 is 5661131.

It is a happy number.

It is a sphenic number, since it is the product of 3 distinct primes.

It is a cyclic number.

It is not a de Polignac number, because 1311665 - 2²⁰ = 263089 is a prime.

It is a Curzon number.

It is a self number, because there is not a number n which added to its sum of digits gives 1311665.

It is an unprimeable number.

It is a polite number, since it can be written in 7 ways as a sum of consecutive naturals, for example, 6809 + ... + 6998.

It is an arithmetic number, because the mean of its divisors is an integer number (207120).

2^1311665 is an apocalyptic number.

It is an amenable number.

1311665 is a deficient number, since it is larger than the sum of its proper divisors (345295).

1311665 is a wasteful number, since it uses less digits than its factorization.

1311665 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 13831.

The product of its digits is 540, while the sum is 23.

The square root of 1311665 is about 1145.2794418831. The cubic root of 1311665 is about 109.4647551686.

Adding to 1311665 its reverse (5661131), we get a palindrome (6972796).

The spelling of 1311665 in words is "one million, three hundred eleven thousand, six hundred sixty-five".