318638861 has 2 divisors, whose sum is σ = 318638862. Its totient is φ = 318638860.

The previous prime is 318638833. The next prime is 318638891. The reversal of 318638861 is 168836813.

It is a weak prime.

It can be written as a sum of positive squares in only one way, i.e., 316662025 + 1976836 = 17795^2 + 1406^2 .

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-318638861 is a prime.

It is a Sophie Germain prime.

It is a Curzon number.

It is a congruent number.

It is not a weakly prime, because it can be changed into another prime (318638891) by changing a digit.

It is a polite number, since it can be written as a sum of consecutive naturals, namely, 159319430 + 159319431.

It is an arithmetic number, because the mean of its divisors is an integer number (159319431).

Almost surely, 2^318638861 is an apocalyptic number.

It is an amenable number.

318638861 is a deficient number, since it is larger than the sum of its proper divisors (1).

318638861 is an equidigital number, since it uses as much as digits as its factorization.

318638861 is an odious number, because the sum of its binary digits is odd.

The product of its digits is 165888, while the sum is 44.

The square root of 318638861 is about 17850.4582854335. The cubic root of 318638861 is about 683.0192024853.

The spelling of 318638861 in words is "three hundred eighteen million, six hundred thirty-eight thousand, eight hundred sixty-one".