1318807817 has 4 divisors (see below), whose sum is σ = 1318890516. Its totient is φ = 1318725120.

The previous prime is 1318807813. The next prime is 1318807873. The reversal of 1318807817 is 7187088131.

It is a happy number.

It is a semiprime because it is the product of two primes, and also a brilliant number, because the two primes have the same length, and also an emirpimes, since its reverse is a distinct semiprime: 7187088131 = 40423 ⋅177797.

It can be written as a sum of positive squares in 2 ways, for example, as 478909456 + 839898361 = 21884^2 + 28981^2 .

It is a cyclic number.

It is not a de Polignac number, because 1318807817 - 2² = 1318807813 is a prime.

It is a Duffinian number.

It is not an unprimeable number, because it can be changed into a prime (1318807813) 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, 8984 + ... + 52137.

It is an arithmetic number, because the mean of its divisors is an integer number (329722629).

Almost surely, 2^1318807817 is an apocalyptic number.

It is an amenable number.

1318807817 is a deficient number, since it is larger than the sum of its proper divisors (82699).

1318807817 is an equidigital number, since it uses as much as digits as its factorization.

1318807817 is an odious number, because the sum of its binary digits is odd.

The sum of its prime factors is 82698.

The product of its (nonzero) digits is 75264, while the sum is 44.

The square root of 1318807817 is about 36315.3936643953. The cubic root of 1318807817 is about 1096.6309638858.

The spelling of 1318807817 in words is "one billion, three hundred eighteen million, eight hundred seven thousand, eight hundred seventeen".