318581 has 2 divisors, whose sum is σ = 318582. Its totient is φ = 318580.

The previous prime is 318569. The next prime is 318589. The reversal of 318581 is 185813.

It is a strong prime.

It can be written as a sum of positive squares in only one way, i.e., 207025 + 111556 = 455^2 + 334^2 .

It is an emirp because it is prime and its reverse (185813) is a distict prime.

It is a cyclic number.

It is not a de Polignac number, because 318581 - 2¹⁰ = 317557 is a prime.

It is a super-2 number, since 2×318581² = 202987707122, which contains 22 as substring.

It is a Sophie Germain prime.

It is a Chen prime.

It is a Curzon number.

It is a plaindrome in base 12.

It is a self number, because there is not a number n which added to its sum of digits gives 318581.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (318589) by changing a digit.

It is a pernicious number, because its binary representation contains a prime number (11) of ones.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 159290 + 159291.

It is an arithmetic number, because the mean of its divisors is an integer number (159291).

2³¹⁸⁵⁸¹ is an apocalyptic number.

It is an amenable number.

318581 is a deficient number, since it is larger than the sum of its proper divisors (1).

318581 is an equidigital number, since it uses as much as digits as its factorization.

318581 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 960, while the sum is 26.

The square root of 318581 is about 564.4298007724. The cubic root of 318581 is about 68.2977857281.

The spelling of 318581 in words is "three hundred eighteen thousand, five hundred eighty-one".