1318312661 has 4 divisors (see below), whose sum is σ = 1318389024. Its totient is φ = 1318236300.

The previous prime is 1318312637. The next prime is 1318312669. The reversal of 1318312661 is 1662138131.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 1662138131 = 113 ⋅14709187.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1318312661 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1318312669) 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, 1376 + ... + 51366.

It is an arithmetic number, because the mean of its divisors is an integer number (329597256).

Almost surely, 2^1318312661 is an apocalyptic number.

It is an amenable number.

1318312661 is a deficient number, since it is larger than the sum of its proper divisors (76363).

1318312661 is an equidigital number, since it uses as much as digits as its factorization.

1318312661 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 76362.

The product of its digits is 5184, while the sum is 32.

The square root of 1318312661 is about 36308.5755848395. The cubic root of 1318312661 is about 1096.4937006781.

The spelling of 1318312661 in words is "one billion, three hundred eighteen million, three hundred twelve thousand, six hundred sixty-one".