1317831665 has 4 divisors (see below), whose sum is σ = 1581398004. Its totient is φ = 1054265328.

The previous prime is 1317831661. The next prime is 1317831673. The reversal of 1317831665 is 5661387131.

It is a semiprime because it is the product of two primes, and also an emirpimes, since its reverse is a distinct semiprime: 5661387131 = 37 ⋅153010463.

It can be written as a sum of positive squares in 2 ways, for example, as 249260944 + 1068570721 = 15788^2 + 32689^2 .

It is a cyclic number.

It is not a de Polignac number, because 1317831665 - 2² = 1317831661 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1317831661) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 131783162 + ... + 131783171.

It is an arithmetic number, because the mean of its divisors is an integer number (395349501).

Almost surely, 2^1317831665 is an apocalyptic number.

It is an amenable number.

1317831665 is a deficient number, since it is larger than the sum of its proper divisors (263566339).

1317831665 is an equidigital number, since it uses as much as digits as its factorization.

1317831665 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 263566338.

The product of its digits is 90720, while the sum is 41.

The square root of 1317831665 is about 36301.9512560964. The cubic root of 1317831665 is about 1096.3603298788.

The spelling of 1317831665 in words is "one billion, three hundred seventeen million, eight hundred thirty-one thousand, six hundred sixty-five".